Microstructure evolution and density behavior of CP Ti parts elaborated by Self-developed vacuum selective laser melting system

This work mainly focuses on the evolution of density behavior and microstructure of commercial pure (CP) Ti parts elaborated by SLM under vacuum system (1 × 10−4 bar) developed at the IRTES-LERMPS laboratory. The mechanism of melt and evaporation process during selective laser melting (SLM) under vacuum environment is also presented in this paper. The surface quality, density and microhardness of Ti samples were measured as a mechanical property. Fine hexagonal crystal structure of α can be found with low scanning velocity, martensitic formation α′ can be observed with high scanning velocity, the method of scanning twice can enlarge the of grain size. A systemic SLM process under vacuum is proposed to calculate the maximum temperature of the molten pool and reveals the evolution of the solidification of melting pool under the laser beam irradiation.