International Journal of Iron & Steel Society of Iran

International Journal of Iron & Steel Society of Iran

Effect of Homogenization on Microstructural Refinement and Hot Ductility René65 Nickel-Based Super Alloys

Document Type : Research Paper

Authors
َA. Mahmoudi
S. M. Abbasi
M. Morakabati
Faculty of Materials and Manufacturing Technologies, Malek Ashtar University of Technology, Tehran, Iran
10.22034/ijissi.2026.2073744.1334
Abstract
In this study, the effect of different homogenization treatments on the Rene65 nickel-based super alloy was investigated. Single-step homogenization was performed at two temperatures, 1100°C and 1150°C, each for a duration of 5 hours. Additionally, a two-step homogenization cycle consisting of 5 hours at each temperature was conducted. The Hot ductility behavior was evaluated through hot tensile test at various temperatures. The results demonstrated that single-step homogenization at the higher temperature of 1150°C led to lower ductility (%10) and brittle fracture characteristics, in comparison to the 1100°C treatment (%45). This reduced ductility is likely due to the presence of low-melting-point secondary phases enriched in zirconium, which promote grain boundary weakening and intergranular failure during high-temperature deformation. In contrast, the twostep homogenization (initially at 1100°C followed by 1150°C), followed by air cooling, resulted in significantly improved ductility (%45) compared to singlestep high-temperature homogenization. This enhancement in ductility may be attributed to the partial retention of interdendritic phases—such as eutectic structures and blade-like precipitates (possibly η-phase)—which did not fully dissolve during homogenization or re-precipitated during rapid cooling. These retained features may act to inhibit excessive grain growth and suppress grain boundary embrittlement.
Keywords
Homogenization
Rene65
Super Alloy
Hot Workability
Subjects
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