Yang Jingjing, Wang Yun, Wei Tongbo, Wang Zemin
The Institute of Technological Sciences, Wuhan University, Wuhan, People's Republic of China.
Xi'an Space Engine Company Limited, Xi'an, People's Republic of China.
3D Print Addit Manuf. 2024 Jun 18;11(3):e1310-e1323. doi: 10.1089/3dp.2022.0302. eCollection 2024 Jun.
The hybrid selective laser melting (SLM) technology by laser welding can capture the superiorities of both processes to produce large-scale, high-quality, high-resolution, and complicated-shaped metallic parts. In this work, the SLMed 304 stainless steel, Inconel 718 superalloy, and Ti-6Al-4V alloy sheets were joined by laser welding under various building directions. And then, the microstructure, microhardness, tensile properties, and corrosion resistance of the laser-welded SLMed 304 stainless steel, Inconel 718 superalloy, and Ti-6Al-4V alloy were compared to explore the effect of SLMed microstructural anisotropy and crystal structure. The results showed that phase constitutions were the same between the SLMed and laser-welded joints for the three alloys. But the grain size and dendrite arm spacings in the joints were coarser than those in the SLMed samples. The SLMed microstructural anisotropy resulted in differences in the thermal gradient, grain size, dendrite arm spacing, and tensile properties in the joints under various welding types. Compared with the SLMed counterparts, the laser-welded 304 stainless steel and Inconel 718 joints showed lower microhardness and tensile properties but better corrosion resistance. In contrast, the laser-welded Ti-6Al-4V joints possess a higher microhardness, tensile properties, and corrosion resistance. Therefore, it is feasible to join SLMed parts to manufacture large-scale parts by laser welding.
通过激光焊接的混合选择性激光熔化（SLM）技术能够兼具两种工艺的优势，从而制造出大规模、高质量、高分辨率且形状复杂的金属零件。在本研究中，对沿不同构建方向通过激光焊接连接的选择性激光熔化成型的304不锈钢、因科镍合金718和Ti-6Al-4V合金板材进行了研究。然后，对比了激光焊接的选择性激光熔化成型的304不锈钢、因科镍合金718和Ti-6Al-4V合金的微观结构、显微硬度、拉伸性能和耐腐蚀性，以探究选择性激光熔化成型的微观结构各向异性和晶体结构的影响。结果表明，三种合金的选择性激光熔化成型部分与激光焊接接头之间的相组成相同。但是接头处的晶粒尺寸和枝晶臂间距比选择性激光熔化成型样品中的更粗大。选择性激光熔化成型的微观结构各向异性导致了不同焊接类型下接头处的热梯度、晶粒尺寸、枝晶臂间距和拉伸性能存在差异。与选择性激光熔化成型的对应部分相比，激光焊接的304不锈钢和因科镍合金718接头的显微硬度和拉伸性能较低，但耐腐蚀性更好。相比之下，激光焊接的Ti-6Al-4V接头具有更高的显微硬度、拉伸性能和耐腐蚀性。因此，通过激光焊接连接选择性激光熔化成型的零件以制造大型零件是可行的。
