两步热处理制备高延性TiAl基合金机理  

Formation mechanism of a high ductility TiAl-based alloy made by two-step heat treatment

作　　者：唐建成[1] 黄伯云[1] 贺跃辉[1] 周科朝[1] 刘文胜[1] 唐志宏[1] 鲁世强[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《中国有色金属学报》2002年第2期221-225,共5页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目 (5 9895 15 0 ) ;国家"八六三"计划资助项目 (715 -0 0 5 -0 0 40 )

摘　　要：研究了两步热处理对锻造Ti 4 7Al 2Cr(摩尔分数 ,% )组织演变和室温拉伸性能的影响。经 12 90℃ ,4h FC12 4 0℃ ,4h ,FC +90 0℃ ,2 4h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 % ,6 77MPa和 5 97MPa。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 。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 1?290?℃, 4hFC1?240?℃, 4?h, FC+900?℃, 24?h, 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%, 677?MPa and 597?MPa respectively. The formation of uniform fine duplex microstructures results from the complex phase transformation of forged microstructures→ γ f+ α f→ γ f+( α f+ γ s+ α s)→ γ f+ L f+ γ s+ L s. When the temperature of the second step heat treatment is lower, the transformation of α s into brittle α 2 phase particles leads to the decrease of room temperature tensile properties.

关 键 词：两步热处理 制备 TIAL基合金 室温拉伸 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TG166[金属学及工艺—金属材料]