TiNiCr形状记忆合金热压缩变形行为研究  

Hot Deformation Behavior of TiNiCr Shape Memory Alloy

作　　者：吴琼[1,2] 杨素媛[1,2] 张晓[1,2] 杨胜男[1,2] 

机构地区：[1]北京理工大学,北京100081 [2]冲击环境材料技术国家级重点实验室,北京100081

出　　处：《稀有金属材料与工程》2016年第6期1631-1635,共5页Rare Metal Materials and Engineering

摘　　要：利用Gleeble-3500在变形温度为600~900℃,应变率为0.001~1 s^(-1)下,对TiNiCr合金进行压缩,对真应力-应变曲线和压缩后试样的显微组织进行分析。结果表明:TiNiCr合金的真应力-应变曲线是由加工硬化效应和软化效应共同决定的,流变应力随温度的升高和应变率的减小而减小;在热压缩过程中,由于软化作用,引起加工硬化效应的位错逐渐消失,合金在不同变形条件下均出现了动态再结晶现象,再结晶机制是弓出形核;温度越高,应变率越低,TiNiCr合金动态再结晶趋势越明显,晶粒尺寸越大,软化机制越以动态再结晶为主;TiNiCr合金与传统非金属间化合物不同,只通过真应力-应变曲线不能推测其软化机制。The hot compressive deformation test of TiNiCr alloy was carried out by Gleeble-3500 in the strain rate range of 0.001～1 s-1 and temperature range of 600～900 °C. The microstructures of TiNiCr after deformation and the true stress-strain curves were studied. The results show that the true stress-strain curves of TiNiCr alloy are affected by the work hardening and softening effect; the flow stress decreases with increasing temperature and decreasing strain rate. During hot compression, the dislocations which result in the hardening decrease because of the softening effect. Dynamic recrystallization occurs under all the deformation conditions and new grains are formed through grain boundaries bulging. The higher the temperature is and the lower the strain rate is, the more obvious the dynamic recrystallization tendency is, the larger the grain size is and the more important the role dynamic recrystallization plays in the softening mechanism. TiNiCr alloy is different from the traditional non-intermetallic compounds, and the softening mechanism can not be speculated only through true stress-strain curves.

关 键 词：TiNiCr合金 热变形 流变应力 再结晶 

分 类 号：TG139.6[一般工业技术—材料科学与工程]