Effects of latent heat in additive manufacturing

Abstract

We analyzed the effects of latent heat in conditions related to the additive manufacturing technology by solving the free boundary problem of a moving heat source. The most important finding of our analysis is a possibility of a genuine (not constitutional) supercooling at the fusion edge of the melt pool. It is measured by the structure forming number of the system, which changes significantly compared to the latent-heat-free system. Other findings of the present treatment are the increase of the longitudinal size and decrease of the maximum temperature of the melt pool due to the latent heat and the role of the surface heat losses in the process. There are several important physical properties, which were not accounted for by the free-boundary model developed in this treatment. They can be accounted for by a phase-field model, which we plan to develop in the future. The latter may also be useful for other technologies, like laser melting, electron (ion)-beam irradiation, and fusion welding.