选区激光熔化成形316L不锈钢组织控制研究

采用选区激光熔化技术, 制备了316L不锈钢3D打印样品, 研究了3D打印体能量密度、微熔池结构和拉伸性能之间的相关性。结果表明, 在实验范围内(打印体能量密度从92.59 J/mm3增大到162.04 J/mm³), 3D打印样品抗拉强度先增大后下降, 体能量密度145.83 J/mm³时, 抗拉强度达到峰值498.48 MPa。熔池的形貌和尺寸与体能量密度相关, 熔池近似面积随体能量密度提高先增大后降低。3D打印样品室温拉伸性能与微熔池的形貌结构有明显相关性, 在拉伸过程中会沿熔池边界发生破坏, 熔池近似面积越大, 熔池边界占比小, 样品抗拉强度相对较高。研究结果可为调控3D打印样品微观组织、改善材料性能提供参考。

Controlling Microstructure of 316L Stainless Steel by Selective Laser Melting Process

A 3D printed sample of 316L stainless steel was prepared by selective laser melting technology,  and the correlation between energy density, molten pool structure and tensile properties of the 3D printed sample was studied. The results show that the tensile strength of 3D printed samples decreases after an initial increase with the energy density varing from 92.59 J/mm3 to 162.04 J/mm³, and reaches the peak value of 498.48 MPa with the energy density of 145.83 J/mm³. The morphology and size of the molten pool are positively correlated with the energy density, and the approximate area of the molten pool  increases followed by a decrease as the  energy density increases. The tensile properties of 3D printed samples at room temperature are obviously correlated with the morphology and structure of the molten pool. A failure is found to be along the boundary of molten pool during the tensile process. It is shown that the larger the approximate area of molten pool, the smaller the proportion of molten pool boundary and the relatively higher the tensile strength of samples. The research results can provide reference for adjusting the microstructure of 3D printed samples and improving the properties of 316L stainless steel by selective laser melting.