Finite element analysis of thermal behavior of metal powder during selective laser melting

Abstract

The thermal behavior during the selective laser melting of metal powders is a key issue to the product quality in 3D printing, so it is of benefit to the development of 3D printing industries to explore the heat transfer characteristics during the selective laser melting process. Based on the TiAl6V4 powder system, the energy conservation equation with a moving Gaussian energy source is developed, in which the temperature-dependent thermal physical properties of materials are taken into account. By means of the finite element methods, the temperature distribution and molten pool dimensions are presented, and the related modeling and numerical methods are validated by previous experimental and numerical works. The effects of the linear energy density, volume shrinkage, scanning track length, hatch spacing and time interval between two neighboring tracks on the temperature distribution and molten pool dimensions are obtained and analyzed. The results show that the increased laser power is superior to the reduced scan speed in thermal performance, which can improve the temperature distribution and molten pool dimensions. Shorter track, shorter hatch spacing and less time interval can lower the temperature gradient and increase the temperature of each track. The average temperature and dimensions of the molten pool are influenced by the volume shrinkage, which should be considered during the numerical simulation.