Thermodynamics analysis and rapid solidification of laser polished Inconel 718 by selective laser melting

Abstract

This paper presents thermodynamics analysis and rapid solidification of laser polishing technology for selective laser melting (SLM) Inconel 718 superalloy. Significant porosity reduction has been examined in the laser polished layer, where the surface porosity is reduced by 65.7% compared with that of the as-fabricated SLM surface. The results show that the temperature in the polished zone is over 1683 K, and the cooling rate is approximately up to 2.46 × 106 K/s. Besides, the polished layer consists of equiaxed grain and columnar grain with average grain size of 10 ± 2.4 μm and 5 ± 1.2 μm, respectively, and tiny cell grains with average size of 3.5 μm in the heat-affected zone (HAZ). Moreover, the transmission electron microscope (TEM) results show that the orientation relationship (OR) between the γ matrix and Laves phase is found to be Burgers OR [011]γ‖[011¯2]Laves on the as-received layer and [1¯11]γ‖[12¯13¯]Laves on the polished layer.