为了研究激光扫描方式对激光选区熔化成形件组织和性能的影响, 采用S形正交和旋转分区两种扫描方式制备了316L不锈钢成形件。测试了成形件的致密度及表面粗糙度, 并对其组织形貌及室温拉伸力学性能进行了对比分析。结果表明, 在其他工艺参数相同的条件下, 用旋转分区扫描方式能够减小成形件的表面粗糙度, 并提高其致密度。旋转分区扫描层内靠近熔合线主要是柱状晶, 熔道中心主要为胞状晶, 晶粒尺寸在 0.4～0.9 μm 之间, 组织比较致密; S形正交扫描的柱状晶区域不明显, 且存在球化的粉末和孔洞, 熔道中心的胞状晶较粗大。旋转分区扫描成形件的室温拉伸强度略高于S形正交扫描成形件, 主要是由于S形正交的成形件存在粉末未熔合及孔洞等缺陷所致。

In order to study the effect of laser scanning method on the microstructure and properties of the selective laser melting formed parts, the 316L stainless steel formed parts were prepared by two scanning methods, S-shaped orthogonal and rotating partition. The density and surface roughness of the formed parts were tested , and the microstructure and tensile mechanical properties at room temperature were compared and analyzed. The results show that under the condition of the same other process parameters, the rotating partition scanning method can reduce the surface roughness of the formed part and increase its density. The scanning zone within the rotating partition is mainly columnar crystals near the fusion line, the center of the melt channel is mainly cellular crystals. The grain size is between 0.4 μm and 0.9 μm, and the microstructure is dense. The columnar crystal region of the S-shaped orthogonal scanning is not obvious, and there are spheroidized powders and holes, and the cell crystals in the center of the melt channel are coarse. The room temperature tensile strength of the rotating partition scanning formed parts are slightly higher than that of the S-shaped orthogonal scanning formed parts, mainly due to defects such as powder incomplete fusion, holes and others in the S-shaped orthogonal formed parts.