High-entropy alloys (HEAs) represent one of the most promising emerging material families, particularly for advanced surface engineering applications. In this work, a near-high-entropy alloy (near-HEA) coating was produced on a 316L stainless steel substrate using laser metal deposition (LMD) from a powder mixture of Inconel 625, Cr and Mo, without the intentional addition of Fe. Due to dilution from the substrate, the resulting alloy contained elevated Fe content while maintaining Cr, Ni and Mo concentrations within the generally accepted compositional range of HEAs. The deposited layer exhibited a dual-phase microstructure consisting of a face-centered cubic (FCC) phase and a highly distorted tetragonal phase forming a periodic network with a characteristic length scale of several hundred nanometers. The hardness of the coating increased to approximately three times that of the substrate, reaching values of 600–700 HV. To further modify the surface properties, laser-induced periodic surface structures (LIPSS) were generated on the polished coating using femtosecond pulsed laser irradiation at different energy densities. The morphology and subsurface structure of the resulting periodic patterns were investigated by scanning electron microscopy. LIPSS with characteristic dimensions ranging from the micrometer to nanometer scale were successfully produced. Cross-sectional analyses revealed that the underlying dual-phase microstructure remained continuous within the laser-structured regions, indicating that LIPSS formation occurred predominantly via metallic ablation without significant phase transformation or amorphization. These results demonstrate the combined applicability of LMD and femtosecond laser structuring for producing mechanically enhanced, micro- and nanostructured near-HEA coatings with potential for advanced surface-related functionalities.

Abstract Laser Metal Deposition is a promising solution for restoring high-value metallic components, but repair operations still lack deposition strategies that can reliably handle irregular, curved, or steep damage profiles. Existing toolpaths are largely adapted from part-fabrication contexts, offering limited control over wall support, curvature alignment, or geometric variability. This work proposes a repair-oriented framework combining damage extraction, boundary reconstruction, and a Support-Oriented Wall Offset (SOWO) strategy. SOWO generates curvature-aware offset paths that initiate deposition at the damaged wall, promoting early support and stable propagation. Six strategies, Raster, Zig–Zag, Contour, Spiral, Hybrid, and SOWO, were evaluated through geometry-driven simulations, parameter sensitivity tests, and thermo-mechanical analyses. Results show that SOWO provides the most balanced performance across coverage, wall engagement, boundary fidelity, and supported deposition, while maintaining continuous motion and adapting to diverse geometries. All validation is simulation-based under identical conditions, enabling fair comparison. The study contributes a generalizable assessment framework and a geometry-aware trajectory that enhances stability in non-planar repair scenarios.

Enhanced Mechanical Performance and Tunable Anisotropy in Low-Cobalt Fe60Mn27Co3Cr10 Dual-Phase High-Entropy Alloy via Laser Metal Deposition

Development of a Johnson-Cook constitutive model for 316L stainless steel manufactured by wire laser metal deposition

Laser metal deposition (LMD) offers high flexibility in material selection. However, processing high‐strength aluminum alloys, like EN AW‐7075, remains challenging due to limited weldability and the evaporation of volatile alloying elements. In this work, solidification cracking is mitigated through grain refinement using TiC nanoparticle as nuclei. The evaporation of zinc and magnesium compromises precipitation‐hardening and solid‐solution‐hardening capacity and thus mechanical properties. This issue is addressed by in situ and ex situ powder blending with additional high Zn and Mg powders, such as ZnAl12 and AZ91. LMD of EN AW‐7075 results in losses of up to 65% Zn and 60% Mg, while EN AW‐5083 shows Mg losses of up to 35%. It is found that the majority of the additional Zn and Mg powders is lost through evaporation, necessitating increased additions. With an addition of 10% ZnAl12 and 5% AZ91, the EN AW‐7075 samples reach a composition according to the standard and are suitable for a heat treatment following T6. With an addition of 10% AZ91, the EN AW‐5083 samples reach a composition desired composition. This strategy highlights the potential for extending the range of processable aluminum alloys in additive manufacturing and opens pathways for the application of high‐strength alloys, such as EN AW‐7075.

Effect of Laser Power on Microstructures and Mechanical Properties of Deposited Ultra-High Strength Steel Processed by Laser Metal Deposition

In-situ technique for absorptivity evaluation from surface temperature measurements in direct laser metal deposition

Rebuilding of stationary shoulder friction stir welding MP 159 probes by laser metal deposition using stellite 6 powder

Porosity, microstructure and performance control of laser metal deposition 17-4PH stainless steel components using laser shock forging method

This study investigates the production and optimization of Ti6Al4V alloy, which is widely used in the aviation sector, by the laser metal deposition method. Despite the advantages of Ti6Al4V, such as high strength, low weight, and corrosion resistance, its production by laser metal deposition method is challenging due to the requirement of a controlled environment. The study examined the geometric structures and porosity values of the samples produced using 12 different process parameters. The number of experiments was reduced, and the most effective parameters were determined using the response surface method and ANOVA. The lower, middle, and upper regions of the test samples produced with optimum parameters were examined separately, and it was determined that the lower regions showed higher strength. It was observed that the Hot Isostatic Pressing and heat treatment applied to the produced samples reduced the strength values but significantly improved ductility and reduced the porosity. In addition, cryogenic heat treatment was applied to the Hot Isostatic Pressing-treated samples to further increase mechanical performance. This process facilitated the completion of martensitic transformation and led to finer and more homogeneous precipitation of carbides while decreasing the porosity ratio and increasing the elongation at break. This study aims to develop the potential of this advanced manufacturing technique in the aerospace sector by comprehensively addressing the effects of process optimization and post-processing in the production of Ti6Al4V by the laser metal deposition method.

Grey cast iron brake discs are widely used in automotive applications due to their excellent thermal and mechanical properties. However, stricter environmental regulations such as Euro 7 demand improved surface durability to reduce particulate emissions and corrosion-related failures. This study evaluates multilayer coatings fabricated by Laser Metal Deposition (LMD) as a potential solution. Two multi-layer systems were investigated: 316L + (316L + WC) and 316L + (430L + TiC), which were primarily reinforced with ceramic additives to increase wear resistance, with their influence on corrosion being critically evaluated. Electrochemical tests in 5 wt.% NaCl solution (DIN 17475) revealed that the 316L + (316L + WC) coating exhibited the lowest corrosion current density and most stable passive behavior, consistent with the inherent passivation of the austenitic 316L matrix. In contrast, the 316L + (430L + TiC) system showed localized corrosion associated with micro-galvanic interactions, despite the chemical stability of TiC particles. Post-corrosion SEM and EDS confirmed chromium depletion and chloride accumulation at corroded sites, while WC particles exhibited partial dissolution. These findings highlight that ceramic reinforcements do not inherently improve corrosion resistance and may introduce localized degradation mechanisms. Nevertheless, LMD-fabricated multilayer coatings demonstrate potential for extending brake disc service life, provided that matrix-reinforcement interactions are carefully optimized.

In the context of Industry 4.0, new methods of manufacturing, monitoring, and data generation related to industrial processes have emerged. Over the last decade, a new method of part manufacturing that has been revolutionizing the industry is Additive Manufacturing, which comes in various forms, including the more traditional Fusion Deposition Modeling (FDM) and the more innovative ones, such as Laser Metal Deposition (LMD) and Wire Arc Additive Manufacturing (WAAM). New technologies related to monitoring these processes are also emerging, such as Cyber-Physical Systems (CPSs) or Digital Twins (DTs), which can be used to enable Artificial Intelligence (AI)-powered analysis of generated big data. However, few works have dealt with a comprehensive data analysis, based on Digital Twin systems, to study quality levels of manufactured parts using 3D models. With this background in mind, this current project uses a Digital Twin-enabled dataflow to constitute a basis for a proposed data analysis pipeline. The pipeline consists of analyzing metal AM-manufactured parts' surface roughness quality levels by the application of a Deep Neural Network (DNN) analytical model and enabling the assessment and tuning of deposition parameters by comparing AM-built models' 3D representation, obtained by photogrammetry scanning, with the positional data acquired during the deposition process and stored in a cloud database. Stored and analyzed data may be further used to refine the manufacturing of parts, calibration of sensors and refining of the DT model. Also, this work presents a comprehensive study on experiments carried out using the CW-GTAW (Cold Wire Gas Tungsten Arc Welding) process as the means of depositing metal, resulting in hollow parts whose geometries were evaluated by means of both 3D scanned data, obtained via photogrammetry, and positional/deposition process parameters obtained from the Digital Twin architecture pipeline. Finally, an adapted PointNet DNN model was used to evaluate surface roughness quality levels of point clouds into 3 classes (good, fair, and poor), obtaining an overall accuracy of 75.64% on the evaluation of real deposited metal parts.

In this study, a multiphysics coupling numerical model was developed to investigate the thermal-fluid dynamics and microstructure evolution during the laser metal deposition of AlCoCrFeNi high-entropy alloy (HEA) coatings on 430 stainless steel substrates. The model integrated laser-powder interactions, temperature-dependent material properties, and the coupled effects of buoyancy and Marangoni convection on melt pool dynamics. The simulation results were compared with experimental data to validate the model’s effectiveness. The simulations revealed a strong bidirectional coupling between temperature and flow fields in the molten pool: the temperature distribution governed surface tension gradients that drove Marangoni convection patterns, while the resulting fluid motion dominated heat redistribution and pool morphology. Initially, the Peclet number (PeT) remained below 5, indicating conduction-controlled heat transfer with a hemispherical melt pool. As the process progressed, PeT exceeded 50 at maximum flow velocities of 2.31 mm/s, transitioning the pool from a circular to an elliptical geometry with peak temperatures reaching 2850 K, where Marangoni convection became the primary heat transfer mechanism. Solidification parameter distributions (G and R) were computed and quantitatively correlated with scanning electron microscopy (SEM)-observed microstructures to elucidate the columnar-to-equiaxed transition (CET). X-ray diffraction (XRD) analysis identified body-centered cubic (BCC), face-centered cubic (FCC), and ordered B2 phases within the coating. The resulting hierarchical microstructure, transitioning from fine equiaxed surface grains to coarse columnar interfacial grains, synergistically enhanced surface properties and established robust metallurgical bonding with the substrate.

Development of a Drainage Device for Local Dry Underwater Laser Metal Deposition of Ti6Al4V Reactive Alloy

High-temperature deformation mechanisms in a high-Nb TiAl alloy fabricated by laser metal deposition

Research on annular laser shaping and intensity profile for laser metal deposition

High heat flux testing of wire-based laser metal deposition coated plasma-facing components

A generalized model for predicting the optimal overlap rate and height of successive single-layer involved in laser metal deposition process based on the aspect ratio

ABSTRACT Laser-metal deposition (LMD) is a cutting-edge additive-manufacturing technique for fabricating bio-implants. This study systematically examines the influence of microstructural evolution in as-built and solution-treated LMD-fabricated 316L stainless-steel on corrosion behaviour and mechanical performance. Although microstructural differences are observed between the top and bottom sections of the as-built specimen, solution-annealing homogenizes the structure. Superior corrosion resistance and surface-film hardness are noted for solution-treated specimens immersed in Ringer’s-Lactate solution for 1 to 30 days. Mechanical performance is assessed through in vitro tensile and strain-controlled fatigue tests while specimens were immersed in Ringer’s-Lactate solution at 37 °C. These experiments simulate a critical loading condition that an implant typically experiences in a biological atmosphere. Interestingly, the solutionized alloy shows superior ductility and fatigue resistance in a biomedical environment, at the expense of strength. The study highlights as-built LMD-316L stainless-steel for high-strength applications, whereas the solutionized version is vital for prolonged service under repeated loading.

Reducing Porosity in LPBF-Fabricated AlSi10Mg Weld Metal via Laser Metal Deposition Welding and Heat Treatment