【摘要】 研究了淬火/回火热处理中淬火温度和回火时间对Ti48Al2Cr0.5Mo合金晶粒细化的影响。研究结果表明:一定的淬火/回火热处理能将粒径约为1 000 μm的铸态组织细化成为18～30 μm的均匀双态组织。TiAl基合金的细化效果与淬火阶段的加热温度密切相关,温度升高,得到的块状组织较细,羽毛状组织体积分数减少。在两相区回火时,高温淬火组织的回火组织较细,而随时间的延长晶粒长大,但不明显。此外,从理论上探讨了淬火/回火工艺细化TiAl基合金显微组织的机理。更多还原

【Abstract】 By tempering the quenching samples in the α+γ phase field, a very fine duplex microstructure (18～30 μm) is obtained in cast Ti-48Al-2Cr-0.5Mo alloys with an initial grain size of about 1 000 μm. The refining effect is found to be greatly dependent on the quenched microstructure which is controlled by prior heating temperature. With increasing the quenched temperature, the quenched microstructures are developed to be finer, and the volume fraction of feather microstructure decreases. During tempering, larger grain is formed with increasing time. The microstructure 18 μm in tempering for 3 h at 1 250℃ is obtained in the samples quenched at 1 400℃. The mechanism of grain refinement in TiAl base alloy is also discussed theoretically in present work.更多还原