Simultaneous enhancement of elevated temperature strength and ductility in additive-manufactured nickel-based superalloy via doping Y2O3 nanoparticles

In this work, we coated a layer of Y2O3 particles in Hastelloy X (HX) nickel-based superalloy powder by in situ chemical method and combined with laser powder bed fusion (LPBF) technology to develop a high-performance Y2O3-doping alloy, designated as Y-HX. The results show that the doping of Y2O3 particles prevents crack formation during the printing process and reduces solute segregation at cell and grain boundaries by increasing the viscosity of the molten pool. The doping of Y2O3 particles to the printed Y-HX alloy enhances grain boundary characteristics, transforming coarse sheet-like carbides into finely dispersed granular carbides at the boundaries during subsequent heat treatment. Additionally, doping with Y2O3 particles increases the recrystallization activation energy of the Y-HX alloy from 149.4 to 278.8 kJ mol–1. At 750 °C, the Y-HX alloy exhibits an ultimate tensile strength of 619 ± 2 MPa and an elongation of 52 % ± 2 %, along with an ultimate tensile strength of 325 ± 3 MPa and an elongation of 47 % ± 2 % at 900 °C. Our work provides a promising way to develop additive-manufactured superalloys with exceptional thermal stability and remarkable high-temperature mechanical properties.