The selective laser melting (SLM) process suffers from a relatively low surface quality in the produced parts. Laser surface remelting has been studied as a reasonable solution to this limitation. Previous studies of the remelting process mostly focused on enhancing the surface quality in gaseous atmospheres. In this study, we proposed an underwater laser remelting process to better control the surface quality of SLM parts. In order to systematically characterize this new process, laser surface remelting experiments were carried out underwater and in argon atmospheres on SLM parts made of Ti-6Al-4V powder. The effects of processing parameters, namely the remelting repetition times, beam scanning pattern, and fill-spacing on the resultant surface roughness and hardness were analyzed. The results show that laser surface remelting in the underwater environment can be a feasible and effective alternative method to control the surface quality of titanium parts processed by SLM.

选择性激光熔化（SLM）工艺在生产的零件中具有相对较低的表面质量。已经研究了激光表面重熔作为对此限制的合理解决方案。先前对重熔过程的研究主要集中在提高气体气氛中的表面质量。在这项研究中，我们提出了水下激光重熔工艺，以更好地控制SLM零件的表面质量。为了系统地表征这一新工艺，在水下和氩气氛中对由Ti-6Al-4V粉末制成的SLM零件进行了激光表面重熔实验。分析了加工参数（即重熔重复时间，光束扫描图案和填充间距）对所得表面粗糙度和硬度的影响。