两步热处理制备高延性TiAl基合金机理
来源期刊：中国有色金属学报2002年第2期
论文作者：唐建成 黄伯云 贺跃辉 周科朝 刘文胜 唐志宏 鲁世强
文章页码：221 - 225
关键词：TiAl基合金；热处理；室温拉伸
Key words：TiAl-based alloy; heat treatment; room temperature tensile
摘 要：研究了两步热处理对锻造Ti-47Al-2Cr(摩尔分数，%)组织演变和室温拉伸性能的影响。经1290℃，4h1240℃(FC)，4hFC+900℃，24h热处理后，锻造TiAl基合金中形成了均匀细小的双态组织，其室温伸长率, 室温抗拉强度和室温屈服强度分别为3.5% , 677MPa和597MPa。在热处理过程中，锻造TiAl基合金发生了复杂的相变，其相变 过程为：变形组织→γf+αf→γf+(αf+γs+αs)→γf+Lf+γs+Ls。当第二步热处理温度偏低时，αs转变为脆性α2相颗粒，降低了合金的室温拉伸性能。
Abstract: The effect of two-step heat treatment on the microstructure evolution and room tensile properties of forged Ti-47Al-2Cr (mole fraction, %) was investigated. After the heat treatment of 1290℃， 4h1240℃(FC)，4h，FC+900℃， 24h，the uniform fine duplex microstructures are formed in forged TiAl-based alloy and its room temperature tensile ductility，tensile strength and yield strength reach 3.5%， 677MPa and 597MPa respectively. The formation of uniform fine duplex microstructures results from the complex phase transformation of forged microstructures→γf+αf→γf+(αf+γs+αs)→γf+Lf+γs+Ls. When the temperature of the second step heat treatment is lower，the transformation of αs into brittle α2 phase particles leads to the decrease of room temperature tensile properties.
