高铌TiAl合金蠕变变形的原位观察  

In Situ Observation of High Nb Containing TiAl Alloy in Creep Deformation

作　　者：余龙[1] 宋西平[1] 张敏[1] 林均品[1] 焦泽辉[2] 于慧臣[2] 

机构地区：[1]北京科技大学,北京100083 [2]北京航空材料研究院,北京100095

出　　处：《稀有金属材料与工程》2014年第4期881-885,共5页Rare Metal Materials and Engineering

基　　金：国家"973"计划项目子课题(2011CB605506)

摘　　要：研究了近片层Ti-45Al-8Nb-0.2W-0.2B-0.1Y合金在750和800℃时短时蠕变行为,并进行了扫描电镜原位观察。结果表明:在750℃蠕变时,合金具有稳定的蠕变特征,随应力提高,稳态蠕变阶段变短,其蠕变应力指数为7.5;在800℃蠕变时,低应力下具有明显的稳态蠕变阶段,其蠕变应力指数为4.0,而高应力下几乎没有稳态蠕变,直接进入加速蠕变。SEM原位观察表明,其蠕变损伤过程是微裂纹的形成、长大及相互连接;随温度升高,裂纹扩展和连接速度变快。A short-term creep behavior of a nearly lamellar Ti-45Al-8Nb-0.2W-0.2B-0.1Y alloy was investigated by a constant stress tension and SEM in-situ observation at 750 ℃ and 800 ℃. The results show that with the stress increasing, duration of the steady-state creep decreases at 750 ℃ and 350-470 MPa and the apparent stress exponent is 7.5. When creeping at 800 ℃, the alloy exhibits a steady-state creep under low stress and the apparent stress exponent is 4.0, while there is almost no steady-state creep and the alloy becomes quickly instable under high stress. SEM in-situ observation shows that the creep damage of the alloy is composed of formation, growth and interconnection of the micro-cracks, and the speed of crack propagation and connection is faster at higher temperature.

关 键 词：TIAL 蠕变 应力指数 原位观察 

分 类 号：TG146.23[一般工业技术—材料科学与工程]