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Research on Post-processing Microstructure and Property of Titanium Components with Selective Laser Melting (SLM)
摘要： Additive manufacturing of titanium component holds promise to deliver benefit such as reduced cost, weight and carbon emissions during both manufacture and use. To capitalize on the benefits, it must be shown that the mechanical performance of parts produced by additive manufacturing can meet design requirement that are typically based on wrought material performance properties. Of particular concern for safety critical structures is the fatigue property of parts produced by additive manufacturing. Microstructure evolution, and its influence on mechanical properties of the alloy in the as-fabricated condition, has been documented by various researchers. However, fatigue crack propagation and the effects of the directional structure have not been sufficiently studied, imposing a barrier for this technology’s potential extension to high-integrity applications. In this study, fatigue life (S-N) and fatigue crack growth (FCG) both parallel and perpendicular to the build directions was studied. The interaction between the directional as-fabricated SLM microstructure and FCG was investigated and compared to that of the hot isostatic pressing (HIP) specimens with and without the stress relief after fabricating with SLM.
关键词： Titanium Components,Selective Laser Melting (SLM),Hot Isostatic Pressing (HIP),Fatigue Property,Microstructure
更新于2025-09-19 17:13:59
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Effect of Hot Isostatic Pressing on Al-10%Si-0.4%Mg Alloy Fabricated by Selective Laser Melting; レーザ積層造形により作製したAl-10%Si-0.4%Mg合金における熱間等方加圧処理の影響;
摘要： In this study, we investigated the effects of hot isostatic pressing (HIP) on the mechanical properties of an Al-10%Si-0.4%Mg alloy fabricated by selective laser melting (SLM). In addition, the effect of internal porosity on the mechanical properties of the alloy was also investigated. After the HIP, the internal porosity of the alloy decreased, while its elongation to failure (EL) improved significantly. However, the 0.2% proof stress (PS) and the tensile strength (TS) of the HIPed alloy were significantly lower than those of the as-built state. This can be attributed to the microstructural changes that occurred at elevated temperatures during the HIP. In addition, the PS and TS of the as-built alloy decreased with an increase in the internal porosity. On the other hand, in the case of the HIPed alloy, the PS and TS were not affected by the internal porosity. However, EL was sensitive to the internal porosity. The EL of the HIPed alloy decreased with an increase in its initial internal porosity. This is because the diffusion bonding during the HIP was imperfect owing to the presence of oxidized scales. Hence, it is imperative to optimize the laser irradiation conditions for the fabrication of aluminum alloy by SLM.
关键词： aluminum alloy,selective laser melting (SLM),hot isostatic pressing (HIP),additive manufacturing (AM),internal porosity
更新于2025-09-11 14:15:04
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Influence of heat treatment under hot isostatic pressing (HIP) on microstructure of intermetallic-reinforced tool steel manufactured by laser powder bed fusion
摘要： Microstructure and properties of as-built laser powder bed fusion (LPBF) steels differ from the conventional ones, and they may contain some porosity and lack of fusion. Therefore, post-treatments, including hot isostatic pressing (HIP), are used to densify the material, and tailor the properties of the final product. Usually, HIP is performed as an operation separate from heat treatment. In the present investigation a new approach was used, in which the whole cycle of the heat treatment was carried out in HIP under pressure, and the influence of HIP on microstructure of an advanced stainless maraging tool steel manufactured by LPBF was investigated. For a comparison, a conventional steel grade of the same chemical composition, after a heat treatment at the same temperature-time conditions, was also characterized. The microstructure of the steel was investigated by means of advanced microscopy and atom probe tomography. The influence of the manufacturing route, heat treatment and HIP on microstructure, austenitic phase fraction and size distribution of precipitates was investigated, and the role of high pressure in stabilization of austenite in the microstructure was discussed. It was concluded that since HIP influences phase transformations, a fundamental understanding of the influence of HIP on microstructure is necessary, and development of new post processing regimes guaranteeing the best performance of the material is required.
关键词： Hot isostatic pressing (HIP),Atom probe tomography,Transmission electron microscopy,Maraging steel,Precipitation hardening,Laser powder bed fusion
更新于2025-09-11 14:15:04