采用激光增材制造技术制备了05Cr15Ni5Cu4Nb沉淀硬化不锈钢板件, 分析了沉积态、调整态、固溶态组织经时效热处理后的显微组织、析出相及力学性能, 并优化了热处理工艺。结果表明: 沉积态组织主要由外延生长的柱状晶组成, 柱状晶内包含多个胞状枝晶, 枝晶间存在残余铁素体, 沉积态组织抗拉强度为1128.5 MPa。经时效热处理后, 残余铁素体消除, 马氏体板条中弥散分布NbC颗粒和大量纳米级ε-Cu相。与沉积态组织相比, 时效态组织的显微硬度和拉伸强度均有大幅提高, 直接时效态和固溶时效态组织的塑性稍有降低, 但抗拉强度分别达1440 MPa和1367 MPa; 调整时效态组织可获得良好的强韧性配比, 延伸率与抗拉强度分别为16%和1164.5 MPa。

The 05Cr15Ni5Cu4Nb precipitation-hardening stainless steel plate is fabricated by the laser additive manufacturing technique. The microstructure, precipitated phase and mechanical property of the as-deposited, adjusted and solid solution state microstructures after aging heat treatments are analyzed, and the technology for the heating processing is optimized. The results show that the as-deposited microstructure mainly consists of epitaxial columnar grains where there are several cellular-like dendrites and residual ferrite exists in the inter-dendritic region. The tensile strength of the as-deposited state microstructure is 1128.5 MPa. After aging heat treatments, the residual ferrite is eliminated, the NbC particles and a large number of nano-sized ε-Cu phases distribute dispersedly in the martensite lath. There are significant increase in both the microhardness and the tensile strength. Compared with that of the as-deposited state microstructure, the plasticity of the direct-aging and solid-solution-aging state microstructure is lower, but the tensile strengths are 1440 MP and 1367 MPa, respectively. The adjusted state microstructure has a favorable ratio of strength and toughness, and the elongation rate and tensile strength are 16% and 1164.5 MPa, respectively.