In the present research, AISI 420 stainless steel (420SS) samples were fabricated by the laser powder bed fusion (LPBF) process. The microstructure, grain morphology, crystallographic texture, and mechanical properties of the 420SS deposits were evaluated in both as-printed and heat-treated conditions. In the as-printed condition, the melting pool boundaries were formed, and the martensite laths and needles were observed, with 13.3% retained austenite. Most of the grains exhibit {111}//BD and {110}//BD fiber textures. After heat treatment, the melting pool boundaries were dissolved. Then, the tempered martensite phase was formed, and the carbides were precipitated from the martensite matrix. The phase is fully martensitic, and the grains mostly align to {111}//BD and {110}//BD fiber textures. Generally, the tensile strength and yield strength increased after heat treatment; however, it leads to a decrease in elongation. This behavior is associated with carbide precipitation and the elimination of the austenite phase in the heat-treated condition. Nevertheless, the toughness measured in the heat-treated condition was much higher than the as-printed condition, owing to the formation of tempered martensite during heat treatment. The LPBF 420SS in the as-printed condition has mechanical properties superior to than that of the reported values in the literature. Moreover, the mechanical properties of LPBF 420SS in the heat-treated condition were found to be better than the wrought material under the same condition.

在本研究中，AISI 420不锈钢（420SS）样品是通过激光粉末床熔合（LPBF）工艺制备的。在印刷和热处理条件下均对420SS沉积物的微观结构，晶粒形貌，晶体织构和力学性能进行了评估。在印刷状态下，形成熔池边界，并观察到马氏体板条和针状组织，残余奥氏体含量为13.3％。大多数晶粒表现出{111} // BD和{110} // BD纤维质地。热处理后，熔池边界被溶解。然后，形成回火的马氏体相，并且碳化物从马氏体基体中析出。该相是完全马氏体的，并且晶粒大部分与{111} // BD和{110} // BD纤维织构对齐。通常，热处理后抗拉强度和屈服强度增加；但是，导致伸长率降低。此行为与热处理条件下的碳化物沉淀和奥氏体相的消除有关。然而，由于在热处理过程中形成回火马氏体，因此在热处理条件下测得的韧性比印刷时高得多。印刷状态下的LPBF 420SS的机械性能优于文献报道的机械性能。此外，发现在相同条件下，LPBF 420SS在热处理条件下的机械性能要优于锻造材料。此行为与热处理条件下的碳化物沉淀和奥氏体相的消除有关。然而，由于在热处理过程中形成回火马氏体，因此在热处理条件下测得的韧性比印刷时高得多。印刷状态下的LPBF 420SS的机械性能优于文献报道的机械性能。此外，发现在相同条件下，LPBF 420SS在热处理条件下的机械性能要优于锻造材料。此行为与热处理条件下的碳化物沉淀和奥氏体相的消除有关。然而，由于在热处理过程中形成回火马氏体，因此在热处理条件下测得的韧性比印刷时高得多。印刷状态下的LPBF 420SS的机械性能优于文献报道的机械性能。此外，发现在相同条件下，LPBF 420SS在热处理条件下的机械性能要优于锻造材料。印刷状态下的LPBF 420SS的机械性能优于文献报道的机械性能。此外，发现在相同条件下，LPBF 420SS在热处理条件下的机械性能要优于锻造材料。印刷状态下的LPBF 420SS的机械性能优于文献报道的机械性能。此外，发现在相同条件下，LPBF 420SS在热处理条件下的机械性能要优于锻造材料。