The development of a high-performance Ni-superalloy additively manufactured heat pipe

Abstract

Additively manufacturing (AM) has been used to manufacture fine structures with structured/engineered porosity in heat management devices. In this study, laser powder bed fusion (LPBF) was used to manufacture a high-performance Ni-superalloy heat pipe, through tailoring LPBF process parameters to fabricate thin wall and micro-channel. By using novel laser scanning strategies, wick structure heat pipes with maximised surface-area-to-volume ratio, fine features size around 100 µm, and controlled porosity were successfully fabricated. Microscopy and X-ray microtomography (micro-CT) were used to investigate the 3D structure of the void space within the pipe. Wick test results showed that most of the heat pipes made by LPBF had better performance than the conventionally manufactured pipes. This study also investigated the influences of the process parameters on the porosity volume fraction and the feature size. The results showed that LPBF process could fabricate thin structure due to the change of melt pool contact angle. The relationship between process parameters and bead size reported in this study could help design and manufacture heat pipe with complex fine structure.