Microstructure evolution and mechanical properties of a novel γ'phase-strengthened Ir-W-Al-Th superalloy

• 作者: Jie-Ren Yang Xiao Fang Yi Liu Zi-Tong Gao Ming Wen Rui Hu
• 来源期刊: 稀有金属（英文版）
• 年，卷（期）: 2021,（12）
• 所属期刊栏目: ORIGINAL ARTICLES
• 页码范围: 3588-3597
• 页数: 10页
• 语种: 英文

摘要

The present work introduces a novel γ'phase-strengthened Ir-W-Al-Th superalloy for ultrahigh-temper-ature applications.First,the as-cast microstructure and phase transformation of Ir-13W-6Al-0.15Th (at％) alloy during solid solution and aging were investigated.Phase transformation was observed during heat treatment.The primary γ'phase disappeared via the redissolution of γ'→ γ at 1800 ℃.The recrystallization took place at 1450 ℃ and very fine equiaxed γ'/γ grains formed after 240 h.The cold-rolled microstructure indicated that the room-temperature γ phase was brittle and cracks mainly emerged along grain boundaries.Ir-13W-6Al-0.15Th alloy exhibited a higher nanohardness than other Ir-based superalloys and pure Ir,which can be attributed to the solid solution and precipitation (γ') strengthening.In addition,the as-cast Ir-13W-6Al-0.15Th alloy shows a medium room-temperature compressive yield strength and good ductility.