Development of Yttria-stabilized zirconia reinforced Inconel 625 metal matrix composite by laser powder bed fusion

Abstract Ni-based superalloys can withstand a temperature of around 1400 K, while the gas turbine can endure a temperature of around 1800 K thanks to thermal barrier coatings such as Yttria stabilized zirconia (YSZ). The present work attempts to introduce a method for modifying commercial Inconel 625 metal powder to enhance the properties of the additively manufactured component for high temperature applications. Inconel 625 was modified by decorating the particles with submicron Yttria-stabilized zirconia (YSZ) particles in order to develop a metal matrix composite material. The goal of this modification was: 1) to enhance the mechanical properties of the Inconel 625 parts after laser powder bed fusion (LPBF) additive manufacturing; 2) to modify the microstructure of the LPBF parts. The influence of LPBF process parameters on surface integrity, microstructure, porosity, and microhardness of the fabricated samples was analyzed for both Inconel 625 and YSZ decorated Inconel samples. Wide ranges of laser power (50–150 W), and volumetric input energy densities (30–270 J/mm3) were examined to fabricate the parts. A Microhardness increase of 30% was observed in laser-fused composite samples after decorating the initial Inconel 625 powder particles with 1 wt% of YSZ. In addition, the microstructural analysis revealed that the addition of YSZ submicron particles stimulates heterogenous nucleation and results in microstructure refinement during LPBF of Inconel 625.