激光熔覆在航空航天领域的应用

… laser cladding. This paper shows that by using this process, protective coating materials can be clad onto aerospace component … laser cladding presents clear advantages for the repair …

PurposeThe purpose of this paper is to demonstrate the preliminary work on using laser cladding technology for the restoration of structural integrity.Design/methodology/approachThe primary methodology used in this research is to develop a laser cladding‐based metal deposition technique to articulate restoration of structural geometry affected by corrosion damages. Following from this method, it is planned to undertake further work to use the laser cladding process to restore geometry and the associated static/fatigue strength.FindingsThis work has found that it is possible to use laser cladding as a repair technology to improve structural integrity in aluminium alloy aircraft structures in terms of corrosion reduction and geometrical restoration. Initial results have indicated a reduction of static and fatigue resistance with respect to substrate. But more recent works (yet to be published) have revealed improved fatigue strength as measured in comparison to the substrate structural properties.Originality/valueThe research is based on an acceptable materials processing technique.

… use of laser cladding to repair non-critical structural aircraft components. This paper summaries the current research and applications and of the research on laser cladding of steel …

… Laser cladding is presently used to repair high volume aerospace, automotive, marine, rail or … The ultimate application of laser cladding is to build components up from nothing, using a …

Advanced remanufacturing by additive manufacturing is challenging in aerospace due to the minimization of material costs, preparation times and metal waste. This study analyzed a 40HM low-alloy steel ring as a demo tooling used to produce aircraft engine components. The possibility of using laser cladding with powder process with the additive material NiCrBSi alloy powder was analyzed. Optimal parameters of the process were selected in terms of the assumed structural requirements (geometrical parameters of the clad, its hardness and the size of the heat-affected zone) for the remanufactured surfaces, ultimately obtaining a crack-free multilayer coating with a thickness of 2 mm and a hardness of above 700 HV1. The remanufacturing process was performed on three representative surfaces: flat face, cylindrical external, and internal. This approach allowed an analysis of the possibilities of finishing the laser-deposited layers with the machining methods used in the actual tooling department of the aerospace company: turning, milling, grinding, and center grinding. During chip processing, the defects (holes, cracks) made machining difficult and ineffective, mainly due to accelerated tool wear. Single cracks were observed after the grinding operation, which may reduce the durability of the remanufacturing layer. Both the changes in the microstructure of the demo component and the phases present in the cladding were analyzed. The deposition process was found to form a martensitic structure in the substrate at the cross-section in proximity to the remanufactured surfaces. This was also confirmed by an increase in average hardness from 402 HV1 to 605 HV1 for the analyzed substrate areas.

The present work reviews the laser cladding process as a repairing technique and the conventional repairing techniques and different heat source models. In this review work, the authors have tried to address the various traditional methods studied for repairing and surface modification. The dominantly used heat source model for numerical modelling of the repairing techniques and the mechanism of the laser cladding process, along with its advantages over the conventional repairing techniques, is also reviewed. This paper also focuses on the predominantly used laser of high power for the cladding process and the effect of process parameters on the quality of the clad layer. The different materials used as clad materials for repairing purposes during the laser cladding process have also been discussed briefly. In this paper, the authors have surveyed literature from different regions of the globe and considered the literature since 1969. This review discusses the various conventional repairing techniques used for repairing, heat source model, process parameters, and different materials used in the laser cladding process. The authors have also briefed the advantages, disadvantages, and application in each of the sections. The use of laser cladding for in-situ repairing process, development of a precise model, use of low-power laser, and application of laser cladding for actual engineering components was also considered in future research work.

… describes laser cladding technology, which is being increasingly applied in the repair and … , aerospace, shipbuilding and ship repair, navy, defense and many other industries. …

… With respect to the principal current market of metallic coatings applications produced by LASER cladding , we have the coating of aircraft gas turbines. Showing, once again the sense …

… hinge joint of the aircraft fuel system through laser cladding. However, laser cladding is a non… vital for the quality and performance of the repaired layer. This paper proposes a combined …

… The effect of laser cladding on the fatigue and fracture behavior under variable … of laser cladding process to repair high value complex fatigue critical aerospace military components, that …

… to implement the repairing work. In this study, repairing complex blades from aerospace engines … Based on the model, the blade was built-up through a laser cladding process and then …

… This paper presents an innovative based adaptive laser cladding methodology for obtaining … of the part, providing a unique solution to solve the part-to-part variation repair problem in …

… deposition by laser cladding has a vast scope in repair of worn out aerospace structures, … application of the process for in situ repair applications for die and aerospace components. …

In-service damage from corrosion, wear or debris impact is increasingly common with ageing military aircraft fleets. Maintenance of this type of “ageing damage” can be expensive and have significant impact on fleet availability. DSTO (Defence Science and Technology Organisation) and DMTC (Defence Materials Technology Centre) are looking at a number of surface modification/or repair technologies that can be used on an opportunity basis to restore geometry or restore the life of an aircraft component. The basis of the technology selection was that there should be low risk with the technology, and the risk is in developing an approved process for the application to aircraft. With the advent of small high-powered lasers, laser cladding (LC) is one of the surface modification technologies examined. It uses a high-powered laser beam to melt a deposited layer of material onto a substrate. Laser cladding could offer significant through-life cost savings, as a repair alternative to the replacement of damaged components. DSTO and DMTC have demonstrated that laser cladding technology could potentially be used to repair or refurbish a range of different damaged components. This paper briefly summaries the current research work on laser cladding of 7xxx series aluminum alloys and discusses potential applications and a certification path for repair of aircraft components in the near future.

… -based techniques are of outstanding importance for the related applications in mould and tool, aircraft and aerospace, as well as automotive industry. Many laser cladding solutions …

The production of reliable turbo machinery, particularly gas turbine blades, is a major global challenge. This capability serves as a key indicator of a nation’s industrial base, technological prowess, and comprehensive strength. Critical components in aircraft engines and gas turbines operate under extreme conditions, including high temperatures, high pressures, and substantial mechanical stresses. Consequently, there is a growing urgency to develop cost-effective and time-efficient repair strategies to enhance engine performance and efficiency. However, many mission-critical parts, especially high-pressure (HP) blades, are prone to severe damage. Moreover, taking equipment offline for blade maintenance and repair is a time-consuming process. It is also highly costly to restore these essential components to full functionality. Since 1996, researchers have focused on applying laser metal deposition (LMD) additive manufacturing technology for high-performance repair and remanufacturing of aerospace engines and industrial gas turbine (IGT) blades. Empirical studies have demonstrated that depositing a high-quality, erosion-resistant protective coating on the leading edge of HP blades effectively extends the service life of turbine blades in both aircraft engines and industrial gas turbines. This study systematically outlines the technical workflow of the proposed methodology and provides a concise perspective on emerging development trends.

… Since one of the main objectives of this work was to develop a cheap turbine blade … chambers to protect the laser impact zone from the atmospheric air during laser cladding. …

Abstract Maintenance, repair and overhaul of components are of increasing interest for parts of high complexity and expensive manufacturing costs. In this paper a production process for laser metal deposition is presented, and used to repair a gas turbine burner of Inconel 718. Different parameters for defined track geometries were determined to attain a near net shape deposition with consistent build-up rate for changing wall thicknesses over the manufacturing process. Spot diameter, powder feed rate, welding velocity and laser power were changed as main parameters for a different track size. An optimal overlap rate for a constant layer height was used to calculate the best track size for a fitting layer width similar to the part dimension. Deviations in width and height over the whole build-up process were detected and customized build-up strategies for the 3D sequences were designed. The results show the possibility of a near net shape repair by using different track geometries with laser metal deposition.

… Laser Metal Deposition (LMD) uses a laser beam as a precise high-energy heat source to melt metal powders … net shape manufacturing and repair of turbine compressor airfoils. In: The …

… Laser direct deposition provides an attractive and cost effective means … turbine airfoils based on a new semi-automated geometric reconstruction algorithm and a laser direct deposition …

… Laser metal deposition is an already established repair and manufacturing technique in the field of turbine … A corresponding technology for repair of TiAl turbine blades does not exist so …

… An additional ring nozzle is applied in [13] to cover deposited material in LMD build-up of a turbine blade. The main disadvantage of additional nozzles is a decreased geometrical …

… LMD (Laser metal deposition), an recently evolved next dimension of additive based manufacturing, not only permits fabrication of parts with intricate shapes and dimensions, but makes …

… algorithm based on direct metal deposition to repair a damaged Nistelle 625 alloy turbine blade. The geometry of the restored blade matched the original blade’s geometry well, with an …

Laser directed energy deposition (LDED) was used with a powder blend comprising 75 wt.% Rene 142 and 25 wt.% of Merl 72 (4275M72) for turbine blade tip repair applications. Sound samples could be deposited at ambient temperature on Haynes 230. The microstructural analyses showed the presence of fine gamma prime precipitates in the as-deposited samples, while after aging, the alloy possessed around 40 vol.% with a bimodal precipitate size distribution. Also, the alloy contained Ta-Hf-W carbides in different sizes and shapes. Tensile testing from room temperature up to 1366 K was performed. The 4275M72 deposits possessed higher tensile properties compared to Rene 80 in this temperature range but lower elongations at the elevated temperatures. The creep properties of 4275M72 samples at 1255 K were superior to Rene 80. Also, the oxidation resistance of deposited 4275M72 was similar to Rene 142. The combination of high mechanical properties, creep behavior, and oxidation resistance of LDEDed 4275M72 makes it a suitable alloy for tip repair of turbine blades.

… like steam turbine blades, gas turbine blades and BlisKs. the … Laser Metal deposition (LMd) for the repair and of high-… and deposition processes) and near net shape deposition (resulting …

In this paper, restoration of nickel-base turbine blade knife-edges with controlled Laser Aided Additive Manufacturing (LAAM) process was investigated. The alloy contains about 9 weight percent Ti/Al composition, which makes it difficult to repair due to the cracking issue. Infrared temperature signal emitted from melt pool was adopted for process control. The deposition with and without process control was compared. The deposition with process control can avoid the hot-cracking which often occurs during deposition of nickel-base super-alloys. The results showed that the process control can also guarantee a better dimensional accuracy. The microstructure of the deposited layers in the cross-section was examined under both microscope and SEM. It displayed directionally solidified fine columnar dendrites which grew following the change of the heat conduction condition. The EDX line scanning verified that chemical composition remained homogeneous distribution in the deposited thin wall. Spot EDX analysis identified that TiC is most likely the main type of carbides formed at the grain boundaries. The results demonstrated that the LAAM process is feasible for the recondition of the gas turbine blade knife-edges.

Laser metal deposition (LMD) — also referred to as laser deposition welding — has been a well-established process for years. One example of its use is for tip repair for gas turbine blades from Siemens. The decision to also implement laser welding technology for the service of industrial steam turbines was based primarily on the fact that repairs — especially conventional welds and coatings including heat treatment and testing — are very time consuming and are very difficult to reconcile with the overhaul periods planned by customers. The robot supported automation of the LMD process and the fact of its lower heat input, reduced layer thicknesses and the resulting lowered deformation of the part due to reduced coating areas makes it possible to optimize lead times. The high level of process automation and reliability of a laser welding process represents another important benefit. Similarly, process parameters are constantly monitored and tracked, to ensure that the required quality standards are maintained and even increased. Furthermore, laser metal deposition completely replaced the conventional processes such as tungsten inert gas method (TIG), plasma transferred arc (PTA) and detonation spraying. In addition the technology unleashes now the possibility to repair and refurbish parts instead of new manufacturing, and therefore delivery times can be tremendously reduced. Based on the decision to six-axis robots it becomes possible enhancing the LMD process for complex 3D surfaces. After modeling a digital twin in Siemens NX CAM it is possible to generate, optimize and simulate the whole motion-sequences offline before starting the LMD process in the robot cell. So already designed parts in 3D-CAD can be used to develop the final robot program. In addition already existing technologies like 3D surface scanning will be implemented in the chain to support the LMD process. Digitalization turns from a buzzword to an established technology for industrial steam turbine manufacturing and repair.

… using the laser metal deposition process, and this is one of the reasons why this additive manufacturing process is an important one. The laser metal deposition process of metals and …

… components such as turbine blades, vanes, and impellers [49,50,51]. Remanufacturing of obsolete or failed tooling is made possible with the laser metal deposition technology even for …

… Bi and Gasser [22] investigated the feasibility of repairing a worn turbine blade knife edge using laser metal deposition process with effective melt pool control. The turbine blade is …

While repair is mainly used to restore the original part geometry and properties, hybrid manufacturing aims to exploit the benefits of each respective manufacturing process regarding either processing itself or resulting part characteristics. Especially with the current implementation of additive manufacturing in the production of TiAl, turbine blades for both hybrid manufacturing and repair new opportunities are enabled. One main issue is the compatibility of the two or more material types involved, which either differ regarding composition or microstructure or both. In this study, a TNMTM-alloy (Ti-Nb-Mo) was manufactured by different processes (casting, forging, laser additive manufacturing) and identically heat-treated at 1290 °C. Chemical compositions, especially aluminum and oxygen contents, were measured, and the resulting microstructures were analyzed with Scanning Electron Microscopy (SEM) and High-energy X-ray diffraction (HEXRD). The properties were determined by hardness measurements and high-temperature compression tests. The comparison led to an overall assessment of the theoretical compatibility. Experiments to combine several processes were performed to evaluate the practical feasibility. Despite obvious differences in the final phase distribution caused by deviations in the chemical composition, the measured properties of the samples did not differ significantly. The feasibility of combining direct energy deposition (DED) with either casting or laser powder bed fusion (LPBF) was demonstrated by the successful build of the dense, crack-free hybrid material.

Laser additive manufacturing using directed energy deposition (LAM-DED) is an advanced manufacturing process widely deployed for fabricating near net-shaped engineering components. LAM-DED has been successfully used for processing wide variety of pure metals and their alloys. The list of these metals and alloys is appending rapidly. Among the various materials successfully deployed for LAM-DED, nickel super alloys are extensively used for various engineering applications due to the unique combination of superior properties, such as high temperature strength, oxidation, corrosion resistance, etc. Recent studies show that LAM-DED built nickel super alloys finds wide applications in aerospace and automotive sector for fabricating engineering components, repairing, remanufacturing, and cladding. Considering the importance of LAM-DED and nickel super alloys, significant amount of work is already reported. This paper presents a comprehensive review on LAM-DED of nickel super alloys. It introduces LAM technology and nickel super alloys with a compilation of various lasers and processing parameters deployed for LAM-DED of nickel super alloys. The paper compiles the metallurgy, mechanical properties, processing issues, and effect of post-processing on LAM-DED built nickel super alloys. This paper will serve as a quick-start for novices to understand LAM-DED of nickel super alloys and will be useful as a reference document for researchers and industrialists in the field.

Directed Energy Deposition (DED) processes have emerged as a pivotal additive manufacturing technique for fabricating high-performance components using superalloys. The ability to predict microstructural evolution in these alloys during DED is critical for ensuring desired mechanical properties and structural integrity. This study presents a theoretical model for predicting the microstructural evolution of superalloys under the complex thermal and mechanical conditions inherent in DED processes. The proposed model integrates thermodynamic principles, kinetic simulations, and phase-field modeling to capture the interactions between thermal gradients, solidification dynamics, and phase transformations. Key variables include deposition parameters, cooling rates, and alloy composition, which collectively influence grain growth, dendritic structures, and precipitation behavior. By incorporating computational thermodynamics, the model enables real-time predictions of phase stability and morphology changes during deposition and solidification. Finite element analysis (FEA) is utilized to simulate the thermal cycles and stress distributions that drive microstructural changes. Additionally, the model accounts for the effects of multiple thermal cycles, such as reheating and remelting, which significantly impact grain refinement and residual stresses. Machine learning techniques are employed to refine predictions by analyzing large datasets generated from experimental and simulated results. The model is validated through experimental studies on nickel-based superalloys using advanced characterization techniques, including electron microscopy and X-ray diffraction. Results demonstrate the model's capability to accurately predict grain structure, phase distribution, and mechanical property variations, thereby providing insights into optimizing process parameters for improved material performance. This study establishes a foundational framework for understanding and controlling microstructural evolution in superalloys during DED processes. The theoretical model offers significant potential for enhancing the reliability and efficiency of additive manufacturing in industries such as aerospace, energy, and automotive, where superalloys are extensively used.

… into large complex components for aerospace applications. Directed energy deposition (DED), one of the additive manufacturing (AM) technologies, offers a high deposition rate, being …

… Laser directed energy deposition (LDED) is an emerging technique for fabricating superalloy based aero engine components. Hence, the current work investigates the tribological …

Titanium Aluminide (TiAl) alloys are intermetallics that offer low density, high melting point, good oxidation and corrosion resistance compared to Ni-based superalloys. As a result, these alloys are used in aero-engine parts such as turbine blades, fuel injectors, radial diffusers, divergent flaps, and more. During operation, aero-engine components are subjected to high thermal loading in an oxidizing and corrosive environment, which results in wear and other material damage. Replacement of the entire component may not be desirable due to long lead time and expense. In such cases, repair and refurbishing may be the best option for the reclamation of TiAl parts. Unfortunately, approved repair technology is not currently available for TiAl based components. Additive Manufacturing (AM) based Directed Energy Deposition (DED) may serve as an option to help repair and restore expensive aero-engine parts. In this work, a review of efforts to utilize the DED technique to repair damaged TiAl-based aerospace parts locally is conducted. Replacing the entire TiAl part is not advisable as it is expensive. DED is a promising technique used to produce, repair, rework, and overhaul (MRO) damaged parts. Considering the high-quality standard of the aircraft industry, DED repaired TiAl parts to be certified for their future use in the aircraft is very important. However, there are no standards for the certification of TiAl repaired parts is reported. Case studies reveal that DED is under consideration for repair of TiAl parts. Hybrid technology comprising machining, repair and finishing capability in a single machine is an attractive implementation strategy to improve repair efficacies. The review shows that the investigations into development and applications of DED-based repairing techniques are limited, which suggests that further investigations are very much needed.

… Ni-based superalloys produced via additive manufacturing (… additively manufactured Ni-based superalloys AMS-OR was … temperature durability for aerospace and energy applications. …

… in aerospace turbofan engines due to its excellent high-temperature performance and machinability. Directed energy deposition (… is developed for blade deposition. The printed blade is …

The feasibility of NASA HR-1 powder reuse for laser powder directed energy deposition (LP-DED) of thin-walled structures in the as-built surface condition was investigated in this study. …

… 718 (IN718) superalloy components can achieve great … were repaired by laser-directed energy deposition (LDED), a … brittle Laves precipitates in the deposition region with only slight …

In the circular economy, products, components, and materials are aimed to be kept at the utility and value all the lifetime. For this purpose, repair and remanufacturing are highly considered as proper techniques to return the value of the product during its life. Directed Energy Deposition (DED) is a very flexible type of additive manufacturing (AM), and among the AM techniques, it is most suitable for repairing and remanufacturing automotive and aerospace components. Its application allows damaged component to be repaired, and material lost in service to be replaced to restore the part to its original shape. In the past, tungsten inert gas welding was used as the main repair method. However, its heat affected zone is larger, and the quality is inferior. In comparison with the conventional welding processes, repair via DED has more advantages, including lower heat input, warpage and distortion, higher cooling rate, lower dilution rate, excellent metallurgical bonding between the deposited layers, high precision, and suitability for full automation. Hence, the proposed repairing method based on DED appears to be a capable method of repairing. Therefore, the focus of this study was to present an overview of the DED process and its role in the repairing of metallic components. The outcomes of this study confirm the significant capability of DED process as a repair and remanufacturing technology.

… laser direct metal deposition processes of the nickel-based powders and fabrication of a full-density, functionally graded, and crack-free structures on the maximum deposition rate for …

… , such as high-temperature Ni superalloys are subject to cracking … of widely used ZhS6K (Russian grade) superalloys with >50% of … Laser-based directed energy deposition was used to …

The microstructure and mechanical behavior of a printable AMSC-DB superalloy fabricated by laser direct energy deposition (LDED) have been systematically investigated in this work. …

Cobalt superalloys such as Tribaloys are widely used in environments that involve high temperatures, corrosion, and wear degradation. Additive manufacturing (AM) processes have been investigated for fabricating Co-based alloys due to design flexibility and efficient materials usage. AM processes are suitable for reducing the manufacturing steps and subsequently reducing manufacturing costs by incorporating multi-materials. Laser directed energy deposition (laser DED) is a suitable AM process for fabricating Co-based alloys. T800 is one of the commercially available Tribaloys that is strengthened through Laves phases and of interest to diverse engineering fields. However, the high content of the Laves phase makes the alloy prone to brittle fracture. In this study, a Ni-20%Cr alloy was used to improve the fabricability of the T800 alloy via laser DED. Different mixture compositions (20%, 30%, 40% NiCr by weight) were investigated. The multi-material T800 + NiCr alloys were heat treated at two different temperatures. These alloy chemistries were characterized for their microstructural, phase, and mechanical properties in the as-fabricated and heat-treated conditions. SEM and XRD characterization indicated the stabilization of ductile phases and homogenization of the Laves phases after laser DED fabrication and heat treatment. In conclusion, the NiCr addition improved the fabricability and structural integrity of the T800 alloy.

… Ni-based superalloys have attracted increasing attention in aerospace, automotive and energy … Compared with cast and deformed Ni-based superalloys, Ni-based powder superalloys …

… based superalloys with a broad, customizable spectrum of mechanical properties via directed energy deposition … the tailoring of superalloy properties for diverse aerospace components. …

… the aerospace supply chain. In this chapter, we analyze the characteristics of aerospace … of applying AM to the aerospace industry and potential future aerospace applications. …

Abstract Additive manufacturing (AM) is transforming all segments of the aerospace industry, including commercial and military aircraft, space applications, as well as missiles systems. Such transformation is due to the unique ability of AM to produce parts with complex designs, reduce manufacturing costs (material waste, assembly due to part consolidation, and the need for tools and fixtures), and fabricate parts with premium materials with small production runs and short turnaround times. AM allows the realization of advanced part designs that provide additional space, multifunctional parts, multimaterial parts, part consolidation, and parts that are difficult to machine. The capability of AM to fabricate freeform designs makes it very suitable for the aerospace industry. To date, aerospace companies, such as Boeing, have installed tens of thousands AM parts (including 200 unique nonmetallic part references) on 16 commercial and military aircraft. It has also started the production of titanium AM parts that will allow savings of up to three million USD per aircraft in the near future. GE Aviation is using metal AM to manufacture thousands of fuel nozzles annually for its new LEAP engine. Similarly, Airbus is utilizing metal AM brackets and bleed pipes on its aircraft. It is currently collaborating with Arconic on the production of large-scale AM airframe components and expects to produce 30 t of AM metal parts by December 2018. The main applications of AM in the aerospace industry are rapid prototyping, rapid tooling, and repair, as well as direct digital manufacturing (DDM) of parts made of metal, plastic, ceramic, and composite materials. Currently, the fastest growing application is DDM (final part manufacturing). For metal parts, the main AM technologies in aerospace applications are directed energy deposition and powder bed fusion. For nonmetallic parts, the dominant AM technologies are vat photopolymerization, material jetting, and material extrusion. This chapter reviews the applications, benefits, and opportunities of AM for the aerospace industry, describes the relevant AM technologies, and discusses the current challenges and potential applications.

… bilayer by using laser additive manufacturing … surface finishing [66]. Compared to Fused Deposition Modeling (FDM), the Selective Laser Sintering (SLS) technique gives a better surface …

Additive manufacturing (AM) is a transformative technology that has rapidly grown over the past decade. AM processes build parts layer by layer and have found applications in the aerospace, biomedical, and automotive fields. The technology holds particular promise for the aerospace industry due to the reduced process time, weight savings of parts, and opportunities for new material development. Herein, a review of laser‐based AM processes, existing AM systems, and aerospace parts being fabricated is presented. It further explores the material properties and microstructure of printed samples with both powder bed fusion and direct energy deposition processes. The benefits and challenges associated with the widespread use of the technology are discussed with emphases on the aerospace sector. Finally, the steps required for parts produced by AM processes to become certified for use in aerospace applications are presented.

This paper reviews recent improvements in additive manufacturing technologies, focusing on those which have the potential to produce and repair metal parts for the aerospace industry. Electron beam melting, selective laser melting and other metal deposition processes, such as wire and arc additive manufacturing, are presently regarded as the best candidates to achieve this challenge. For this purpose, it is crucial that these technologies are well characterised and modelled to predict the resultant microstructure and mechanical properties of the part. This paper presents the state of the art in additive manufacturing and material modelling. While these processes present many advantages to the aerospace industry in comparison with traditional manufacturing processes, airworthiness and air transport safety must be guaranteed. The impact of this regulatory framework on the implementation of additive manufacturing for repair and production of parts for the aerospace industry is presented.

The additive manufacturing and 3-dimensional manufacturing technology offer unparalleled flexibility in terms of part geometry, material composition and manufacturing time. There are many difficulties in manufacturing parts in the aerospace field. Thin-walled aircraft engine components and structures with complex geometry, the difficulties encountered in the processing of materials, are the other main factors that compel the aviation industry to adopt the use of additive manufacturing technology. It is progressing in the direction of radically changing the aerospace sector in the production of extremely complex and lightweight parts with material wastes that are almost none. The aerospace engine industry requires stronger, lighter and more durable components. Today's additive manufacturing technology provides new possibilities to meet these situations. In addition, the aviation industry has combined the additive manufacturing process from concept design to end-use parts and repairs. Areas of application include rapid prototyping of components in the design phase using plastic and metal, followed by repair of damaged parts instead of direct production, scrapping or replacement of mold, tool and complex shape metal parts for mass production. Laser Metal Spool (LMD) Technology is the best method to repair aviation components. In this study, research and development activities carried out in the field of additive manufacturing in the aerospace industry have been examined and a literature review has conducted. In the experimental study, a scaled 3D prototype of an exemplary rocket equipment was produced using 3D printer technology. The pressure parameters of the study have been examined.

This study investigates the fundamentals of the simultaneous coating and roller burnishing process as a novel approach for improving the surface and subsurface properties of EHLA-deposited material. The combination of EHLA and roller burnishing yields significant improvements in surface roughness, microhardness, and residual stress distribution. The residual heat from the EHLA process was observed to increase surface plasticity during simultaneous processing, significantly influencing the effectiveness of roller burnishing as a function of the tool center point (TCP) offset parameter Δz. Surface finish is most favorably affected at a moderate Δz of 4 mm, suggesting the existence of an optimal thermal window for surface smoothing. The highest hardness was achieved at the smallest offset (Δz = 1 mm), potentially due to precold deformation effects and stress-assisted martensitic transformation. In terms of residual stress modification, all burnishing strategies succeeded in transforming high subsurface tensile stresses into beneficial compressive stresses, which are expected to enhance bending fatigue performance. The TCP offset further allowed directional stress control, enabling differentiated axial and circumferential stress profiles. Further studies are required to explore the relationship between the observed residual stress profiles and the corresponding fatigue resistance of repaired components under service-relevant loading conditions.

The article presents a new AM (Additive Manufacturing) process development, necessary to repair parts made from Aluminum 6061 material, with T6 treatment. The laser Directed Energy Deposition (DED) and Extreme High-Speed Directed Energy Deposition (EHLA) capabilities are evaluated for repairing Al large components. To optimize the process parameters, single-track depositions were analyzed for both laser-powder DED (feed rate of 2 m/min) and EHLA (feed rate 20 m/min) for AlSi10Mg and Al6061 powders. The cross-sections of single tracks revealed the bonding characteristics and provided laser-powder DED, a suitable parameter selection for the repair. Three damage types were identified on the Al component to define the specification of the repair process and to highlight the capabilities of laser-powder DED and EHLA in repairing intricate surface scratches and dents. Our research is based on variation of the powder mass flow and beam power, studying the influence of these parameters on the weld bead geometry and bonding quality. The evaluation criteria include bonding defects, crack formation, porosity, and dilution zone depth. The bidirectional path planning strategy was applied with a fly-in and fly-out path for the hatching adjustment and acceleration distance. Samples were etched for a qualitative microstructure analysis, and the HV hardness was tested. The novelty of the paper is the new process parameters for laser-powder DED and EHLA deposition strategies to repair large Al components (6061 T6), using AlSi10Mg and Al6061 powder. Our experimental research tested the defect-free deposition and the compatibility of AlSi10Mg on the Al6061 substrate. The readers could replicate the method presented in this article to repair by laser-powder DED/EHLA large Al parts and avoid the replacement of Al components with new ones.

… and the EHLA technique. The investigation covered thermal processes, microstructural evolution, mechanical properties, and corrosion resistance. The EHLA-… Notably, the EHLA sample …

The article presents a new AM (Additive Manufacturing) process development, necessary to repair parts made from aluminum 6061 material, with T6 treatment. The laser DED and EHLA capabilities are evaluated for repairing Al large components. To optimize the process parameters, single track depositions were analyzed for both conventional DED (feed rate of 2m/s) and high-speed DED/EHLA (feed rate 20m/s), for AlSi10Mg and Al6061 powders. The cross sections of single tracks revealed the bonding characteristics and provided a suitable parameter selection for the repair. Three damage types were identified on the Al component, to define the specification of the repair process and to highlight the capabilities of DED and EHLA in repairing intricate surface scratches and dents. Our research is based on variation of the powder mass flow and beam power, studying the influence of these parameters on the weld bead geometry and bonding quality. The evaluation criteria include bonding defects, crack formation, porosity and dilution zone depth. The bidirectional path planning strategy was applied with a fly-in and fly-out path for the hatching adjustment and acceleration distance. Samples were etched for a qualitative microstructure analysis and the HV hardness was tested. The novelty of the paper is the new process parameters for DED and EHLA deposition strategies, to repair large Al components (6061 T6), using AlSi10Mg and Al6061 powder. Our experimental research tested the defect-free deposition and the compatibility of AlSi10Mg on the Al6061 substrate. The readers could replicate the method presented in this article, to repair by DED/EHLA large Al parts and avoid the replacement of Al components by new ones.

This review provides a comprehensive overview of high-wear-resistant metal–ceramic surface engineering technologies based on Directed Energy Deposition (DED) for high-temperature industrial applications. In high-temperature processes such as continuous hot-dip coating, critical components (e.g., rollers and sleeves) are exposed to severe wear and chemical reactions, leading to rapid degradation and frequent replacement, which results in significant economic losses. This review focuses on the fundamental characteristics of DED processes and their advantages over conventional surface modification techniques such as HVOF, PVD/CVD, and arc-based methods. Particular attention is given to the process–structure–property relationships governing coating performance, including coating thickness, bonding characteristics, and high-temperature stability. Representative material systems, particularly WC-based metal–ceramic composites (e.g., Co–WC), are systematically discussed in terms of their wear resistance and applicability under severe operating conditions. Quantitative tribological performance metrics, including wear rate and friction coefficient, are also reviewed to provide a more rigorous understanding of coating performance. The analysis highlights that DED offers unique advantages in achieving thick coatings with strong metallurgical bonding and high applicability to repair and remanufacturing of large-scale components. In addition, recent advances in DED technologies, such as closed-loop control, self-regulating effects, and data-driven process optimization, are examined to highlight emerging trends in the field. The review also identifies current technical limitations and outlines future research directions, emphasizing the need for improved process control, defect mitigation, and integration of advanced monitoring techniques.

Extreme high-speed laser material deposition (EHLA) is an adapted variant of directed energy deposition (DED-LB-P/M), also known as laser material deposition, and has been developed for the efficient manufacturing of thin layers with high deposition speeds. With precise control of the energy input into the powder gas jet and the substrate, EHLA allows deposition speeds of up to 200 m/min and weld beads as thin as 25 μm. Advantages include a smaller melt pool and a heat-affected zone, allowing the processing of difficult-to-weld material combinations. The development of EHLA for additive manufacturing (EHLA3D) aims to produce highly customized components with improved structural accuracy compared to standard LMD at increased build rates compared to laser powder bed fusion (PBF-LB/M). A promising application is complex lightweight structures for the aerospace industry. However, there is a lack of systematic investigation on lightweight materials processed with EHLA3D at feed rates >20 m/min. In this work, a specially designed tripod machine (maximum feed rate 200 m/min) was used to investigate the buildup of aluminum in process regimes at 30 m/min. After confirming the existing single-track parameters, the tracks were metallographically examined and checked for pores, cracks, and bonding defects. The process was applied to thin-wall geometries and line energies as well as return-times that were varied. To gain an understanding of process-induced heat development, the process was monitored using thermography. Since the process shows geometry-specific heat flow patterns, guidelines have been developed that enable the buildup using different process adaptions.

… EHLA and DRS are combined in this study to fabricate a novel Ti(N, B)/AISI431 composite … adoption in demanding applications like aerospace, automotive, and heavy machinery. …

… The microhardness and wear resistance values of the coatings … and EHLA coatings were good and had no cracks or defects. Compared with those of the CLA coating, the EHLA coating …

Liquation cracking in the heat-affected zone (HAZ) remains a critical challenge during laser cladding repair of K447A nickel-based superalloy. In this study, the base metal (BM) was pre-…

This review comprehensively examines the durability issues and technological advancements of nickel‐based alloys in high‐temperature service conditions, focusing on oxidation, creep, thermal shock, and corrosion performance, as well as the underlying mechanisms of crack formation and suppression in laser cladding. It first explores the roles and limitations of alloy composition, microstructure control, and surface modification in enhancing high‐temperature oxidation and creep resistance. Then, it thoroughly analyzes the impacts of thermal stress, solidification shrinkage, and elemental segregation during laser cladding on crack formation, and summarizes crack‐suppression strategies like reducing dilution, adjusting laser energy density, altering scanning speed, and adding small amounts of Mo. The review notes that while nickel‐based alloys show significant mechanical and chemical stability in high‐temperature environments, they still face challenges in balancing microstructure and macro‐properties, co‐optimizing multiple properties, and controlling processing costs. Future research should focus on developing multi‐scale, multi‐physical, field‐coupled theoretical models, finely tuning process parameters, and establishing unified evaluation standards to promote the widespread use of nickel‐based alloys in key sectors like aviation and energy.

Cracking of nickel superalloys with a high content of γ’-phase remains an unresolved problem, including in technologies for repairing gas turbine engines blades. Laser cladding is a method of material deposition used to repair parts exposed to aggressive environment and surface wear. Cladding parameters have a high influence on cracking susceptibility nickel superalloys. Alloy ZhS32 has a high propensity for hot cracking when exposed to laser radiation. In this work, the study of the structural and phase features of ZhS32 alloy was carried out. A high tendency to form segregation of refractory elements and carbides in the intergranular areas was found. The features of the structure and phase composition of the material for different cladding parameters were studied. The main contribution of technological parameters to the formation of cracks is shown.

… Laser cladding as an advanced and effective technology has … of nickel-based superalloys. However, crack is a challenging problem for nickel-based superalloys during laser cladding …

… While laser cladding process has flexibility to precisely … is focused on the laser cladding of nickel-based superalloys and its … and refurbishment of components, laser cladding process is …

… cladding speed. This work contributes to the comprehensive understanding of laser cladding, … basis for controlling the microstructure in laser deposited nickel-based superalloy coatings. …

… principle in the laser cladding process for creating clad layers in … to obtain highly efficient clad layers on the substrates. … and microstructure of laser cladding of nickel‑based superalloy. …

… 2 Laser cladding technology … interaction between laser, cladding material, and substrate, which is usually used to enhance the performance of metal surface and repair surface defects …

… Glavicic performs studies on the laser cladding of turbine blades made of Rene N5 alloys. The clad … the laser deposit cladding [13]. Latest approaches show that error-free single crystal …

… Laser cladding, basically a weld deposition technique, is finding applications in many areas including surface coatings, refurbishment of worn out components and generation of …

… of the nickel-based superalloys CMSX-4 and turbine blade tips of PWA 1426. Experiments were carried out to establish laser … This study showed that the combination of cladding and …

Laser cladding is a well-established process to apply coatings on metals. However, on substrates considerably thinner than 1 mm it is only rarely described in the literature. In this work 200 µm thin sheets of nickel-based superalloy 718 are coated with a powder of a cobalt-based alloy, Co–28Cr–9W–1.5Si, by laser cladding. The process window is very narrow, therefore, a precisely controlled Yb fiber laser was used. To minimize the input of energy into the substrate, lines were deposited by setting single overlapping points. In a design of experiments (DoE) study, the process parameters of laser power, laser spot area, step size, exposure time, and solidification time were varied and optimized by examining the clad width, weld penetration, and alloying depth. The microstructure of the samples was investigated by optical microscope (OM) and scanning electron microscopy (SEM), combined with electron backscatter diffraction (EBSD) and energy dispersive X-ray spectroscopy (EDX). Similarly to laser cladding of thicker substrates, the laser power shows the highest influence on the resulting clad. With a higher laser power, the clad width and alloying depth increase, and with a larger laser spot area the weld penetration decreases. If the process parameters are controlled precisely, laser cladding of such thin sheets is manageable.

Abstract A paraxial powder-feeding system by employing a quasi-continuous fiber laser machine was established to repair non-weldable nickel-based K447A alloy. In the present study, the duty cycle (DC) of the pulsed-wave laser was chosen to reveal the influence on hot cracking. The results showed that the total length of hot cracking on the 10.5 mm-length longitudinal section of the cladding zone reduces from 3.263 mm to 0.092 mm with the decline of DC from 80% to 30%. The intermittent occurrence of the laser beam induced the ripple microstructure in the cladding layer (CL). It is the high cooling rate in laser extinguishment process that caused the fine dendrite zone which provides more resistance for hot cracking propagation in the CL. The liquid film in the heat-affected zone (HAZ) mainly results from the M5B3/γ, γ′/γ, and MC/γ constitutional liquation successively among 1200–1300 °C. Heat input is the main factor affecting hot cracking in the HAZ. With the decrease of DC, the dendrite spacing of the fine dendrite zone decreases in the CL, and the depth of liquefaction zone decreases in the HAZ, as a result, the length of hot cracking in the CL and HAZ both decreases.

… ) during long-term service in harsh environments, and laser cladding is a highly efficient method for repairing components. In this work, the laser cladding technique was conducted on …

Laser powder deposition is one of the most promising methods for the repairing of the single crystal Ni-based superalloys components used in the hot-section of gas turbine engines in order to extend their lifetime and reduce their overall cost. The microstructure of Ni-based superalloys deposited on single crystal substrates of similar materials depends mainly on the materials involved, on the orientation of the deposited tracks in relation to the substrate and on the deposition parameters. In the present paper these relations are discussed and illustrated for the case of single and multiple layer depositions of NiCrAlY and Rene N4 on (100) single crystal substrates of SRR99 and CMSX-4 Ni-based superalloys. On the other hand, when the aging treatment is applied directly to the solidification microstructure resulting from laser deposition, abnormal γ/γ′ microstructures may result, due to the inhomogeneity created by alloying elements partition during solidification. Performing a homogenization annealing before aging circumvents this difficulty. The homogenizing annealing also eliminates undesirable brittle phases present in the solidification microstructure, such as carbides and topologically close-packed compounds.

This paper systematically introduces the application status of coating-preparation technology on light alloys in the field of aviation parts repair. Included are the advantages and disadvantages of thermal spraying technology and laser cladding technology in the application process, as well as the research status and application prospects of the emerging cold spray (CS) technology and supersonic laser deposition (SLD) technology. Compared with traditional thermal-spraying technology, CS has many advantages, such as low spraying temperature, low oxygen content of the coating, and low porosity, which can effectively avoid oxidation, burning loss, phase change, and grain length during thermal spraying. CS can prepare oxygen-sensitive, heat-sensitive, amorphous, and nanomaterial coatings that are difficult to prepare by traditional thermal-spraying technology. However, in the preparation of high-strength super-hard alloys, CS has shortcomings such as low deposition efficiency and bonding strength. SLD overcomes the shortcomings of CS while inheriting the advantages of CS. In the future, both technologies will be widely used in repairing and remanufacturing in the field of aviation. Based on the principles of CS and SLD, this paper introduces, in detail, the deposition mechanism of the coating, and the specific application examples of CS in the aviation field at the present stage are described. The research and application status of the two technologies in the fields of anti-corrosion coating, wear-resistant coating, functional coating, repair, and remanufacturing in recent years are reviewed. Finally, the application and development prospects of CS and SLD are discussed.

… industries like automotive, aerospace and biomedical, there is … by laser engineering net shaping (LENS) process and recent state-of-… The microstructure and characterization depict an …

… It was hypothesized that additively combining the two aerospace alloys would form a unique … microstructure, hardness and thermal properties were studied to evaluate feasibility of LENS…

The application of Metal Additive Manufacturing (MAM) in the aerospace industry has been gaining attention. The poor surface quality of parts greatly limits the prospects of MAM-produced parts in the aerospace industry as fatigue performance hinges on a good surface finish and homogeneous microstructure. Post-processing treatments are important to improve the surface quality and the overall performance of MAM-produced parts during static and dynamic loadings. This paper provides a review of the current state of post-processing treatment options for MAM-produced parts. The advances in the post-processing treatments of MAM parts to improve fatigue strength, tensile strength, surface integrity and other properties of parts are reviewed. Future research prospects on metal additive manufacturing of aerospace parts are briefly expounded. Abbreviations: AM: Additive Manufacturing; CMT-WAAM: Cold Metal Transfer-Based Wire Arc Additive Manufacturing; CSD: Cold Spray Deposition; DA: Direct Aging; DED: Directed Energy Deposition; E: Elongation; EBAM: Wire-feed Electron Beam Additive Manufacturing; EBAM Electron Beam Additive Manufacturing; EBSD: Electron Back Scattered Diffraction; FRAM: Friction Rolling Additive Manufacturing; FSAM: Friction Stir Additive Manufacturing; FSP: Friction Stir Processing; HFDB: Hybrid Friction Diffusion Bonding; HIP: Hot Isostatic Pressing; HSA Homogenisation + Solution Treatment + Aging; IFSP: Interlayer Friction Stir Processing; IPF: Inverse Pole Figure; KAM: Kernel Average Misorientation; LAM: Laser Additive Manufacturing Process; LENS: Laser Engineered Net Shaping; LDM: Laser Deposition Manufacturing; L-PBF: Laser Powder Bed Fusion; MAM: Metal Additive Manufacturing; MTFS: Multi-track Multi-layer Friction Surfacing; O-WLAM: Wire Oscillating Laser Additive Manufacturing (O-WLAM); S: Solution Treatment; SA: Solution Treatment + aging; TEM: Transmission Electron Microscope; UAM: Ultrasonic Additive Manufacturing; UTS: Ultimate Tensile Strength; WAAM: Wire Arc Additive Manufacturing; YS: Yield Strength

… With the development of the aerospace industry, the … flow stress and microstructure evolution of aerospace parts and … , enhancing material microstructure, optimizing mechanical …

Abstract Laser Engineered Net Shaping (LENS™) was utilized to create novel silica (SiO2) coatings onto commercially-pure titanium (Cp-Ti). It was hypothesized that if silica could be deposited as a coating via laser surface engineering, high hardness and wear resistance could be added to existing Cp-Ti material. Post-deposition heat-treatments in the form of laser passes (LP) and a furnace residual-stress relief were completed on the coatings and mechanical/material properties were subsequently evaluated. Titanium silicide (Ti5Si3) formation and related dendritic microstructures were identified throughout the coating by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopic (SEM) analysis, and appeared more ordered after stress-relief heat treatment. High hardness values of approximately 1500 HV were measured at the coating’s topmost surface while specific wear rates showed a maximum 98% reduction from 346.2 × 10−6 mm3/N-m in the Cp-Ti substrate to 7.1 × 10−6 mm3/N-m in the heat treated 1 LP coating. In situ tribofilm formation was observed during wear, which indicated self-healing properties from the material and likely aided further in wear reduction. Our results show that silica coating on titanium via laser surface engineering could be used as a suitable manufacturing practice to create hard, Ti5Si3-reinforced ceramic coatings with high wear resistance and self-healing properties for applications ranging from biomedical to aerospace.

… for aerospace applications, the aluminum coating often wears or … to improve the adhesion of the coating to the alloy substrate … Argon gas was used to protect the specimens and lens at a …

Abstract Reactive-deposition additive manufacturing was employed to manufacture titanium-based metal matrix composites for improving the wear resistance and temperature capability of commercially pure titanium (CPTi); a standard material in the aerospace, biomedical, and marine industries, among others. Composites were manufactured by leveraging in situ high-temperature reactions between CPTi, zirconium (Zr), and boron nitride (BN) powders during laser-based directed-energy-deposition (DED) 3D-printing. The effect of Zr and BN on the processability, phase formation(s), surface wear, and mechanical properties of 3D-printed titanium was studied by printing commercially-pure titanium with premixed additions of 20 wt% Zr and 10 wt% BN using Laser Engineered Net Shaping (LENS™). In the as-printed BN-containing structures, phase analysis revealed reinforcing ceramic phases TiN, TiB, and TiB2, whose presence was substantiated through first-principles analysis. The combined addition of Zr and BN produced a Ti-Zr alloy matrix with BN-particle and in situ phase-reinforced microstructure with 450% higher hardness (from 318 ± 26 HV0.1/15 to 1424 ± 361 HV0.5/15), a stabilized sliding−COF within 50 m of reciprocating wear testing, and 9x lower final wear rate in comparison to LENS™ deposited titanium. Zr-addition alone revealed a combined alloyed and particle-reinforced composite with 12% higher hardness, 23% higher compressive yield strength, and an 11% decrease in final wear rate compared to LENS™-produced titanium. Our results demonstrate that reactive-deposition based additive manufacturing can be exploited to create unique coatings and net-shape alloyed structures to enhance the surface and bulk properties of standard engineering materials such as titanium.

… Microstructural analysis, phase analysis using X-ray diffraction, wear resistance and … done on LENS™ processed 3D printed coatings. Coatings showed graded microstructures and in …

… Therefore, a synergy of multiple processes is necessary for blade repair. This paper … of aero-engine blade repair and the influence and contribution of each process to the final surface …

… in aero engine development, manufacturing and repair. Currently … aero engine, for certain components, various design alternatives have to be tested in order to optimize the aero engine …

This paper presents a pulsed laser cladding of TiN-Ti composites used for aero-engine overhaul. In order to analysis the practicability in application, the microstructures, microhardness and other performances of the composite coating were investigated. The results show that the interface between the remanufacturing zone and the substrate is metallurgical bond. The remanufacturing zone is mainly composed of TiN phase and alpha martensite. TiN phases distribute discretely in the remanufacturing coatings and display two typical morphologies, namely the coarse particle TiN and the dendrite TiN. The difference of formation mechanism is the reason why TiN phases display two different morphologies. Compared with the substrate, the repair coatings show better performances on microhardness and wear resistance in same condition. The different performances between remanufacturing coatings and substrate can be mainly attributed to the reinforcement of different TiN phase introduced into the composite coatings. The results above indicate that, it is feasible to repair the aero-engine components by laser cladding of TiN-Ti composites. Keywordslaser cladding; remanufacturing; aero-engine; titanium alloy; wear resistance

Abstract Inconel 718 is one of the most widely used alloys in metal additive manufacturing because of its wide range of applications in aerospace, gas turbines and other structural applications in high temperature range. These high value components may encounter failure or damage within the intended life cycle due to defects introduced during part processing or service conditions. Repairing such components with traditional techniques introduces high residual stresses and microstructural inhomogeneity. Therefore, additive manufacturing (AM) techniques have been used for repairing such high value components. Directed energy deposition (DED) technique has been widely used for repair purposes in aerospace component due to its ability to control microstructure, mechanical properties and maintaining high accuracy. The observations made while working with DED on repairing of aerospace components was analyzed to identify the challenges encountered during the process. Several issues such as the presence of micro-pores near the edges in the deposited component and variation in the microstructure with increase in the deposition height were observed. Therefore, the study was focused to present the role of DED process in the repair of metallic aerospace components and identifying the challenges encountered from the geometrical and metallurgical aspect of the component.

… of damaged aero-engine blades is of great importance in additive or hybrid remanufacturing … In addition to material-missing damages, the blade's surface also deforms due to working in …

… for remanufacturing always takes the key position, because the tool paths for laser cladding … how to extrapolate and extend the blade surface for tip repair through reverse-engineering …

Abstract Nickel based single crystal alloys are extensively employed in aero-engine system involving high temperature conditions due to its superior creep resistance and high strength. The aero-engine parts undergo degradation and affect the functional performance due to extreme and severe service operating environment. Therefore repairing of those parts are economically viable than replacing them with newer ones. Recently metal additive manufacturing technology gaining importance in remanufacturing and repair of engineering parts. Particularly direct metal deposition (DMD) technique has attracted research community due to its versatility particularly for repair activities. However, currently achieving single crystal (SX) microstructure during remanufacturing are challenging and mainly depends on the geometry and shape of the damaged parts. In addition, both geometrical and microstructural integrity in the repaired parts are prime concern for its optimum performance during in-service situations. In this present study the existing status of DMD technique employed and its challenges for remanufacturing of SX based aero-engine parts are addressed.

… [28], a laser repair method has been invented for a high gamma prime content Ni base super alloy substrate surface, with gamma prime content in the range of at least about 30 volume …

… On this basis, the blade surface model is obtained based … laser cladding and remanufacturing blade of an aero-engine was tested. The experimental results show that the blade surface …

… latest turbine blade repair methods involving laser additive … that requires attention in blade surface repair. It is reported that … Brazing has dominated the surface repair of turbine blades. It …

Aero-engine is an essential component of the aircraft. Due to the high cost of raw materials and precise structure, the maintenance cost of aero-engine is great. By repairing worn blades rather than replacing them with new ones, the aero-engine maintenance cost can be reduced effectively. For repairing worn blades, existing methods mainly generate tool path based on the reconstructed surface with the aid of CAM software. In this paper, an effective tool path generation method for repairing blades after additive manufacturing process is presented, which overcomes the low efficiency and complicated process weakness of existing methods. The tool path is generated directly with point clouds without surface fitting. By splitting point cloud and analyzing geometric parameters of points, machining areas could be recognized from the entire blade model. The cutter location point is generated by extending on the normal vector direction of the corresponding point. The five-axis tool path could be obtained by connecting cutter location points in turns. Tool path optimization is further studied after the generation process. These algorithms eliminate the time consumption caused by surface fitting operations, and could generate five-axis tool paths for repairing aero-engine blades efficiently.

Abstract Ti6Al4V alloys are widely recognized for their excellent properties, which make them suitable for aerospace applications. The aero-engine components are subjected to high loading conditions, which sometimes degrade their properties. Thus, replacing the whole component is not an economical way. Therefore, repairing or refurbishment of a component is necessary. Directed metal deposition (DMD) is an additive manufacturing technique employed to repair the aero-engine components. Among other repair manufacturing techniques, this process has gained significant attention in the last few years due to its inherent capabilities. However, there are some issues associated with this technique, like defects, surface roughness, residual stresses, which influence the mechanical properties of a material. Many researchers have paid attention to optimize the directed energy deposition (DED) parameters to improve the properties of a material. In this study, the review of directed energy deposition used to repair Ti6Al4V aerospace components is done. The analysis of the obtained results by some researchers is done here.

Laser machining processes are widely used in the manufacture and repair of aero engine components. This paper provides examples of well-established, cutting-edge and emerging laser machining processes. A well-established process is laser metal deposition or laser cladding which is predominantly used to restore worn blade tips and seal fins. But the process also has the potential to restore complete airfoils of integral rotors, also known as bladed disks or blisks. In the FLEXILAS-project sponsored by the German Federal Ministry of Education and Research it was demonstrated that the quality of laser generated blisk blades is comparable to that of new ones.

Modern aero engine components are subjected to extreme conditions were high wear rate, excessive fatigue cycles, and severe thermal attack are inevitable. These aggressive conditions reduce the service life of components. Its generic ef‐ fect is magnified in the light of understanding the fact that aero engine parts are highly sensitive to functional and dimensional precision; therefore, repair and re‐ placement are great factors that promote downtime during operation. Hard ther‐ mal barrier coatings have been used in recent times due to their optimized properties for maximum load bearing proficiency with high temperature capabili‐ ty to meet performance and durability required. Nevertheless, less emphasis is being given to the coating-substrate interaction. Functionally graded structures have better synergy and flexibility in composition than coatings, giving rise to controlled microstructure and improved properties in withstanding acute state of affairs. Such materials can be fabricated using Laser Engineered Net Shaping (LENSTM), a laser-based additive manufacturing technique. LENSTM offers a great deal in rapid prototyping, repair, and fabrication of three-dimensional dense structures with superior properties in comparison with traditionally fabricated structures. The manufacture of aero engine components with functionally graded materials, using LENSTM, can absolutely mitigate the nuisance of buy-to-fly ratio, lost time in repair and maintenance, and maximize controlled dimension and multi-geometric properties, enhanced wear resistance, and high temperature strength. This review presents an extensive contribution in terms of insightful un‐ derstanding of processing parameters and their interactions on fabrication of functionally graded stainless steel, which definitely influence the final product quality.