Effects of micro-TiC particles on microstructure and mechanical properties of selective laser melting Inconel 625 alloys

The Inconel 625–xTiC (x=0, 2%, 4%, 6%, mass fraction) alloys were prepared by selective laser melting forming technology. The effects of micro-TiC particles on the microstructure and mechanical properties of Inconel 625–xTiC alloys were investigated. The results show that the Inconel 625–xTiC alloys are mainly composed of γ-Ni, TiC, and Laves (Cr₂Nb) phases. With the increase of TiC mass fraction, the microstructure of Inconel 625–xTiC alloys gradually changes from the columnar dendrites in the middle of the melt tracks and the equiaxed crystals at the junction of the melt tracks to the cellular equiaxed crystals and other substructures. When the TiC mass fraction is 6%, the hardness and tensile strength of Inconel 625–xTiC alloys are the highest, which are HV_0.2 (525.3±15.13) and (1440.31±22.33) MPa, respectively; however, the total elongation decreases from (30.0±0.56)% to (3.2±0.98)%.