Glass phase microstructure and mechanical behaviors of laser-remelted Ni30Cr25Al15Co15Mo5Ti5Y5 coating reinforced by α/γ-Al2O3 phase

A novel Ni30Cr25Al15Co15Mo5Ti5Y5 reinforced coating by α/γ-Al2O3 was prepared using supersonic particle deposition (SPD), the coating was remelted to optimize internal structure via laser. Much ultrafine grains (UFGs) (86.5%) and nano-crystal grains (NGs) (13.4%) in the laser-remelted coating reinforced by α/γ-Al2O3 was found because the high melting point of the ultrafine α/γ-Al2O3 hindered the nucleation and crystal growth, the diffusion and redistribution of HEA element atoms could not occur, indicated the formation of a homogeneous metastable supersaturated compound. The dispersed diffraction peak was accompanied by α-Al2O3 dispersion phase in the remelted coating that was macroscopically isotropic. Due to the strengthening effect of the phase particles for α/γ-Al2O3 dispersion phase, most internal stress was released in the HEA coating. Under deep undercooling, the friction and wear resistance was ensured by the remelted coating reinforced by α/γ-Al2O3 strengthening phase due to the glass transition effect of the HEA coating in the supersaturated state.