Fabrication of high porosity Cu-based structure using direct laser sintering

Abstract

Purpose – The purpose of this paper is to report the investigation on obtaining a high-porosity Cu-based structure which was sintered successfully using direct laser sintering and to reveal the mechanisms of obtaining high porosity and acceptable strength simultaneously as well as the effect of NaCl content on characteristics of the sintered samples. Design/methodology/approach – Experimental study has been performed. The powder mixture utilized in this experiment includes metal powder (Cu and Cu3P mixture) and porogen [sodium chloride (NaCl)]. Scanning electron microscope, energy-dispersive X-ray analysis and the Archimedes density measurement were used to detect the characteristics of the sintered sample and to reveal the mechanism of forming high porosity and strength structure. Findings – More than 57 per cent porosity can be achieved while the structural strength is acceptable, and the infiltrated experiment verifies the pores in the structure are inter-connected. During laser sintering, NaCl powder melts and brings a larger amount of liquid phase, inducing large rearrange force and fast rearrangement of Cu particles. Therefore, after NaCl is removed, the dense and strong longer-bar shape tracks with larger amount of pores in the microstructure can be obtained. The size of pores as well as the porosity of the sintered sample increase with the NaCl content in the powder mixture. Originality/value – The mechanism of obtaining high porosity and acceptable strength simultaneously was revealed. The effect of NaCl content on characteristics of the sintered samples was also disclosed.