1073-1173K温度范围内TiAl合金的超塑性行为  

SUPERPLASTICITY OF TiAl BASED ALLOYS AT RELATIVELY LOW TEMPERATURES RANGING FROM 1073 K TO 1173 K

作　　者：孙坚[1] 刘润开[2] 吴建生[1] 贺跃辉[3] 

机构地区：[1]上海交通大学教育部高温材料及高温测试开放实验室,上海200030 [2]福建省漳州市外贸公司 [3]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《金属学报》2001年第1期95-98,共4页Acta Metallurgica Sinica

基　　金：国家自然科学基金!59671006

摘　　要：研究了经热机械处理的ＴｉＡｌ合金在温度１０７３－１１７３Ｋ和２×１０－５－２×１０－４ｓ－１应变速率范围内的超塑性行 为.结果表明，在上述实验条件下ＴｉＡｌ合金表现出良好的超塑性，其最高拉伸延伸率达到５３３％；同时，合金具有较高的应变速 率敏感指数。二计算得到的ＴｉＡｌ合金超塑性变形的表观激活能为２２０ｋＪ／ｍｏｌ．此时ＴｉＡｌ合金超塑性变形主要是受晶界扩散所 控制的晶界滑动机制，同时动态再结晶也是合金超塑性变形的一种协同机制．Superplastic behaviors of thermo-mechanically processed TiAl based alloys were investigated at relatively low temperatures ranging from 1073 K to 1173 K and at strain rates ranging from 2 x 10(-5) s(-1) to 2 x 10(-4) s(-1). The results showed that the alloys exhibit excellent superplasticity, and the maximum tensile elongation reaches 533%. Also, the strain rate sensitivity values are of high level. The apparent activation energy of the alloys for the superplastic deformation was calculated to be 220 kJ/mol. The mechanism of grain boundary diffusion controlled by grain boundary slide is considered to be responsible for the superplastic deformation of the alloys, and the dynamic recrystallization also is the accommodated mechanism for the deformation.

关 键 词：超塑性 显微组织 TIAL合金 热机械处理 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TG113.253[金属学及工艺—金属材料]