Influence of Heat Treatment on the Microstructure and Mechanical Properties of Pure Copper Components Fabricated via Micro-Laser Powder Bed Fusion

Abstract

Pure copper (Cu) is widely used across numerous industries owing to its exceptional thermal and electrical conductivity. Additive manufacturing has facilitated the rapid and cost-effective prototyping of Cu components. Laser powder bed fusion (LPBF) has demonstrated the capability to produce intricate Cu components. However, LPBF-fabricated components exhibit anisotropic features, which stem from their inherent thermal gradients, resulting in properties that depend on the grain orientation. In the present study, pure Cu samples were fabricated via micro-laser powder bed fusion (μLPBF), resulting in improved mechanical properties, specifically, enhanced strength and ductility. The as-printed pure Cu sample exhibited thermal stability owing to its high-density grain boundaries and dislocations, enabling it to maintain relatively high levels of strength and ductility even when exposed to an elevated temperature of 300 °C. Furthermore, the heat treatment resulted in the disappearance of the initial microstructural characteristics, such as molten pool boundaries. As the heat-treatment temperature increased, the anisotropic yield strength decreased. Overall, the anisotropy of the properties of pure Cu components fabricated via μLPBF can be mitigated through heat-treatment-induced microstructural adjustments.