Selective laser melting (SLM) is an additive manufacturing process that builds metal components according to computer-aided design (CAD), selectively fusing and consolidating metal powders one layer at a time. This study systematically investigates the influence of various laser conditions on the microstructure and mechanical properties of Co–Cr–Mo alloy fabricated by SLM. Hot isostatic pressing (HIP) was applied after SLM to further densify the fabricated components, and their microstructures and mechanical properties were compared with those of as-built samples. Parts with relative density of ∼97.17% were obtained with a high-energy laser density and double laser scanning, and subsequent HIP effectively eliminated the majority of pores. X-ray diffraction revealed that γ and ε phases co-existed owing to the high solidification rate during SLM. Directional columnar grains and fine cellular dendrites that were parallel and normal, respectively, to the build direction were observed. Although variations in microstructure resulting from different as-built samples were insignificant, the mechanical properties remarkably changed. The improved mechanical behavior was attributed mainly to increased densification and grain-boundary strengthening. However, the HIP treatment increased the tensile ductility and reduced the yield strength, as a result of the increase in grain size. The tension-fractured surface suggests that mostly quasi-cleavage brittle fracture took place in the SLM-processed parts.

选择性激光熔化（SLM）是一种增材制造过程，可根据计算机辅助设计（CAD）构建金属部件，一次选择性地将一层金属粉末熔融和固结。这项研究系统地研究了各种激光条件对SLM制造的Co-Cr-Mo合金的组织和力学性能的影响。在SLM之后应用热等静压（HIP）来进一步压实所制造的组件，并将它们的微观结构和力学性能与竣工样品进行比较。通过高能量激光密度和双重激光扫描获得相对密度约为97.17％的零件，随后的HIP有效消除了大部分毛孔。X射线衍射表明，由于SLM的高凝固速率，γ和ε相共存。观察到分别与构造方向平行和垂直的定向柱状晶粒和细小细胞树突。尽管由不同的成品样品引起的微观结构变化不明显，但机械性能却发生了显着变化。改善的机械性能主要归因于致密化和晶界强化的增加。但是，由于晶粒尺寸的增加，HIP处理增加了拉伸延展性并降低了屈服强度。拉伸断裂表面表明，在SLM处理的零件中大部分发生了准断裂脆性断裂。尽管由不同的成品样品引起的微观结构变化不明显，但机械性能却发生了显着变化。改善的机械性能主要归因于致密化和晶界强化的增加。但是，由于晶粒尺寸的增加，HIP处理增加了拉伸延展性并降低了屈服强度。拉伸断裂的表面表明，在SLM处理的零件中大部分发生了准断裂脆性断裂。尽管由不同的成品样品引起的微观结构变化不明显，但机械性能却发生了显着变化。改善的机械性能主要归因于致密化和晶界强化的增加。但是，由于晶粒尺寸的增加，HIP处理增加了拉伸延展性并降低了屈服强度。拉伸断裂表面表明，在SLM处理的零件中大部分发生了准断裂脆性断裂。