Physical characteristics of nanoscale titanium-aluminum alloy powder during 3D printing laser sintering process — A molecular dynamics study

Abstract

In this present study, the physical characteristics of nanoscale niobium zirconium alloy powder applied on the powder bed fusion laser sintering is computed during 3D printing process by molecular dynamics simulation method with embedded atom method potential. There are three solid and hollow type powder sizes, which are 16a, 20a, and 24a, respectively. There are three solid and hollow type powder sizes, which are 16a, 20a, and 24a, respectively. Six combinations are created and laser-sintered under different heating rates (1K/ps, 0.5K/ps, and 0.25K/ps, respectively), and then the neck width, radius of gyration, structural change, potential energy, and root mean square displacement of nanoscale alloy powder are analyzed and discussed. It is found that nanoscale niobium zirconium alloy powder has the phenomena of spontaneous solid-state sintering at room temperature. It is observed that the temperature of solid state diffusion decrease with heating rate decreasing when powder size fixed, the temperature of solid state diffusion decrease with powder size decreasing when heating rate fixed also. Average coalescence temperature and melting temperature decrease with heating rate decreasing when powder size fixed, and they decrease with powder size decreasing when heating rate fixed also. It is mentioned that coalescence temperature of nanoscale niobium zirconium alloy powder is about 1250 to 1800K, and melting temperature of that is about 1250 to 1800K (The macroscopic melting of that point is 2070 K). Therefore, it is suggested that the power of laser beams could be lower during 3D printing process in order to heat nanoscale niobium zirconium alloy powder.