Ti3SiC2 reinforced Inconel 625 composites prepared via laser directed energy deposition: New insights into microstructure evolution and mechanical properties

In this study, the Ti3SiC2/IN625 matrix composites was fabricated by laser directed energy deposition technology (LDED). The microstructure evolution and mechanical properties of the fabricated Ti3SiC2/ IN625 composites were studied. The results show that Ti3SiC2 decomposes in the high temperature melt pool due to its unique crystal structure and then combines with the segregated Nb and Mo elements to generate a large number of finesized particle and rod-like carbides. The dendrite growth of the composite becomes more disordered and the primary dendrite spacing of the composites is also reduced. Compared with IN625, the tensile strength of composites at room temperature and high temperature (650 degrees C) were increased by 10.7 % and 20.6 %, respectively. The improvement in strength of the composite was attributed to the increase of precipitated phase and the effect of grain refinement. In addition, the diffusely distributed second phase promoted recovery and recrystallization at high temperature, which made the plasticity ability of composites increasing. This work provides a new idea for the preparation of high temperature nickel-based compound materials by LDED.