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A Hybrid Modeling of the Physics-Driven Evolution of Material Addition and Track Generation in Laser Powder Directed Energy Deposition
摘要： Directed Energy Deposition (DED) is one of the most promising additive manufacturing technologies for the production of large metal components and because of the possibility it offers of adding material to an existing part. Nevertheless, DED is considered premature for industrial production, because the identification of the process parameters may be a very complex task. An original hybrid analytic-numerical model, related to the physics of laser powder DED, is presented in this work in order to evaluate easily and quickly the effects of different sets of process parameters on track deposition outcomes. In the proposed model, the volume of the deposited material is modeled as a function of process parameters using a synergistic interaction between regression-based analytic models and a novel element activation strategy. The model is implemented in a Finite Element (FE) software, and the forecasting capability is assessed by comparing the numerical results with experimental data from the literature. The predicted results show a reasonable correlation with the experimental dimensions of the melt pool and demonstrate that the proposed model may be used for prediction purposes, if a specific set of process parameters that guarantees adequate adhesion of the deposited track to the substrate is introduced.
关键词： laser powder deposition,finite element model,thermal analysis,directed energy deposition,additive manufacturing
更新于2025-09-16 10:30:52
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Microstructure and properties of homogeneous Cu90Fe10 immiscible composites with nanotwins by laser powder deposition: Effect of spot size
摘要： To select the reasonable spot size during laser powder deposition (LPD), the homogeneous Cu90Fe10 immiscible composites were produced by LPD with different spot sizes (2 mm and 4 mm in diameter). The LPD-produced Cu90Fe10 immiscible composites deposited with different spot sizes display a similar microstructure composed of a-Fe/g-Fe and ε-Cu phases. A large amount of nanoscale Fe-rich particles is uniformly embedded within the Cu-rich matrix and the Cu-rich particles with nanotwins are distributed within the Fe-rich particles due to secondary liquid phase separation (SLPS). Moreover, some nanoscale FeCr grains (~20 nm) are precipitated within the Fe-rich particles. Both the averaged diameter and grain size of Fe-rich particles reduce with decreasing the spot size due to higher cooling rate. The immiscible composite produced with spot size of 2 mm exhibits higher microhardness and elastic modulus (1.9 GPa and 143.5 GPa respectively) than the corresponding ones for the counterpart with spot size of 4 mm (1.8 GPa and 142.6 GPa respectively) and Brass. As a result, the LPD-produced Cu90Fe10 immiscible composite deposited with spot size of 2 mm exhibits higher wear and corrosion resistance compared to that deposited with spot size of 4 mm.
关键词： Nanotwins,Wear,Laser powder deposition,Corrosion,Particle-reinforcement
更新于2025-09-12 10:27:22
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[Laser Institute of America ICALEO? 2015: 34th International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing - Atlanta, Georgia, USA (October 18–22, 2015)] International Congress on Applications of Lasers & Electro-Optics - Laser powder deposition of WC particle reinforced metal matrix composites
摘要： Laser Powder Deposition (LPD) is an additive layered manufacturing process that can deposit near-net shape parts directly from metal powder. Metal Matrix Composites (MMCs) combine the merits of ductile metal matrix and hard ceramic reinforcement, providing enhanced properties including hardness and wear resistance. MMCs can be easily implemented in LPD process via blending the powders during deposition of coatings and 3-D parts. However, cracks induced by thermal stress and material embrittlement limit the application of MMCs in direct LPD processes. This study experimentally investigated the mechanical properties of MMCs deposited via LPD. Hardfacing alloy Stellite 6 and ductile alloy Inconel 718 were chosen as the matrix material, respectively, with spherical Tungsten carbide (WC) particles as the reinforcement. According to the experiment results, Inconel 718 was found to be a better choice for matrix material as it presented better compatibility with WC particles with acceptable wear resistance. Influence of direct age heat treatment of Inconel 718 matrix on mechanical properties was also investigated. Tensile tests showed that addition of WC particles in the matrix reduces both the ultimate strength and elongation. Microstructural observation of the tensile specimens indicated that WC particles are the preferable crack initiation sites, which significantly reduces the load-carrying capacity and ductility of the composite. Dissolution of WC into the matrix, which embrittles the matrix and further reduces the ductility of the composite, was proven by micro-hardness test and elemental analysis. Last, dry sliding test is conducted to evaluate the wear resistance of the MMCs. It was found that a small addition of WC particles can significantly increase the wear resistance.
关键词： Inconel 718,wear resistance,Laser Powder Deposition,Stellite 6,WC particles,Metal Matrix Composites
更新于2025-09-11 14:15:04