Two-Phase Matrix of Ni3Al and γ- Ni Coatings Prepared by Laser Cladding

Abstract

As a solid solution matrix alloy, nickel-based alloys have the shortcomings that the strength will decrease with increasing temperature. The significance of this experiment is forming the two-phase matrix, in which γ- Ni solid solution are replaced partly by Ni3Al with potential performance at high temperature. In this paper, no visible cracks and pores Ni3Al/γ- Ni composite matrix coatings were prepared on mild steel substrate by laser cladding with mixed powders of two common thermal spying powders of Ni60AAA alloy and Ni-coated Al. The microstructure and phase constitution of the coating were studied through SEM, EDX and x-Ray diffraction analysis technique. The results show the composite coating consists of γ- Ni, Ni3Al, Cr23C6 and CrB, both the main matrix γ- Ni solid solution and the second matrix phase of Ni3Al being free uniformity dendrite and containing some alloying elements such as Fe, Cr, Si, etc,with the dendrites surrounded continuously by the eutectic. It may be possible for improving high-temperature performance.