<span class="fontstyle۰">Effect of Homogenization on Microstructural Refinement and Hot Ductility René۶۵ Nickel-Based Super Alloys

In this study, the effect of different homogenization treatments on the Rene۶۵ nickel-based super alloy was investigated. Single-step homogenization was performed at two temperatures, ۱۱۰۰°C and ۱۱۵۰°C, each for a duration of ۵ hours. Additionally, a two-step homogenization cycle consisting of ۵ 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 ۱۱۵۰°C led to lower ductility (%۱۰) and brittle fracture characteristics, in comparison to the ۱۱۰۰°C treatment (%۴۵). 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 ۱۱۰۰°C followed by ۱۱۵۰°C), followed by air cooling, resulted in significantly improved ductility (%۴۵) 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.

کلیدواژه ها:

Homogenization ، Rene۶۵ ، Super Alloy ، Hot Workability