工艺参数对选区激光熔化成型316L不锈钢组织结构的影响

选区激光熔化技术(selective laser melting,SLM)在制造高精度复杂零件方面具有很大的优势,这种零件加工方法具有节省材料、低成本和高速度的优点,在机械零件制造、生物医学和发电机制造领域具有广阔的发展前景。为研究不同工艺参数对选区激光熔化成型的316L不锈钢组织结构的影响,通过选择性熔化成型技术制备316L不锈钢材料,分析不同成型方向的晶体结构和工艺参数对材料组织结构的影响,研究不同激光功率和扫描速度下不锈钢结构的变化。结果表明:垂直扫描方向且平行于沉积方向的平面晶体为鱼鳞状,扫描平面晶体为柱状晶且连续外延生长;激光功率和扫描速度的变化将对试样的组织结构产生相应的影响,激光功率偏小会使试样表面产生明显的孔洞现象,激光功率偏大试样表面会在孔洞的基础上产生"球化";扫描速度过小试样表面产生"球化",扫描速度过大则会使试样致密度变小,产生裂纹和孔洞。因此,由激光熔化技术制作的316L不锈钢金属试样需要选择适当的激光功率和扫描速度才能有效减少球化和孔洞的产生。

Effect of Technological Parameters on Microstructure of 316L Stainless Steel by Selective Laser Melting

Selective laser melting technology has great advantages in manufacturing high-precision complex parts in the neighborhood. This kind of parts processing has the advantages of saving materials, low cost, fast speed and so on. It has broad prospects in mechanical parts manufacturing, biomedicine, generator manufacturing and other fields. In order to study the effect of different processing parameters on the structure of 316L stainless steel produced by selective laser melting. 316L stainless steel was prepared by selective melting technology. The effects of crystal structure and processing parameters in different forming directions on the structure of 316L stainless steel were analyzed. The structural changes of stainless steel with different laser power and scanning speed were investigated. The results show that the planar crystals which are perpendicular to the scanning direction and parallel to the deposition direction are fish scales. Scanning plane crystal is columnar crystal and continuous epitaxy growth. The change of laser power and scanning speed will have a corresponding effect on the structure of specimens. The small laser power will cause obvious holes phenomenon on the surface of specimens, and the large laser power will cause spheroidizing on the surface of specimens. If the scanning speed is too small, the surface of the sample will be spheroidized, and if the scanning speed is too high, the density of the sample will be reduced and holes will be formed. It is concluded that the 316L stainless steel metal specimens made by laser melting technology need to select the appropriate laser power and scanning speed to reduce the spheroidization and holes effectively.