Laser welding of a selective laser melted Ni-base superalloy: Microstructure and high temperature mechanical property

Inconel 625 specimens manufactured by selective laser melting (SLM) were welded using a laser welding process. The tensile strength in the welding zone was higher than that of the base material at 815 degrees C. Fractures were observed in the base alloy, but not in the welding zone. The welding zone was mainly composed of columnar grains that exhibited greater resistance to tensile fractures than the as-received SLM alloy with equiaxed grains. The failure was characterized by brittle fractures in the base material, whereas the welding zone featured enhanced plastic deformation ability. The present work established laser welding as a highly efficient method for joining SLM Inconel 625 and for achieving outstanding high temperature performances.