Influence of heat treatment on creep behavior of IN625 coating on a Ni3Al-base superalloy

Abstract

IN625 coatings applied by selective laser melting show high resistance at high temperatures but the creep behavior of such coatings is not well understood. In this paper, the microstructure and creep behavior of this coating applied to Rene80 alloy under different heat treatment conditions, were investigated by a small punch creep test. The results show that coating application in the form of solution heat treatment + coating + aging heat treatment leads the maximum creep life of about 135 h. In cast-coated specimens, liquation cracks due to incomplete solution of γ - γ ′ eutectic, γ ′ phase, Cr-Mo boride, and MC carbide in heat affected zone reduced the creep life by about 63 h. In these samples, unlike the heat treatment sample, which experienced inter-granular creep failure, the failure occurred exactly from the coating-substrate interface.

Keywords

• Small punch creep
• Selective laser melting
• IN625
• Rene80
• Coating