TC11合金β相区大应变热变形行为及组织研究

利用热模拟试验机,在温度为1020～1080℃和应变速率为0．001～70 s~(-1)范围内对TC11合金进行真应变为1．2的大应变等温恒应变速率压缩试验,获悉高温塑性流动的应力-应变关系曲线特征,并对变形前后的微观组织进行观察。结果表明:流动应力随应变速率升高和温度降低而增加,但前者比后者对流动应力的影响更为显著;在所研究的温度范围内,当应变速率大于10．0 s~(-1)时,变形组织主要为拉长的β晶粒;当应变速率在1．0～0．01 s~(-1)之间时,变形试样分别发生部分动态再结晶和完全动态再结晶;当应变速率为0．001 s~(-1)时,变形试样以动态回复为主。为获得良好的变形组织,热加工区域以温度在1020～1050℃,应变速率在0．01～1．0 s~(-1)范围为宜。

Investigation on hot deformation behavior and microstructure of TC11 alloy at large strain during β-phase

The isothermal constant strain rate compression tests of TC11 alloy were conducted up to a large strain of 1.2 in the temperature range 1 020～1080℃and strain rate range 0.001～70.0 s~(-1)by using the Thermecmastor-Z hot working simulator.The characteristic of high temperature plastic flow stress-strain curves was revealed,and the microstructures of the pressed samples with those before pressing were investigated.The results showed that the flow stress increased with the increase of strain rate and the decrease of temperature,but the former influenced the flow stress more markedly than the later.In the temperature range studied,elongatedβgrains were developed in the strain rate range 10.0～70.0 s~(-1),part or full dynamic recrystaUization ofβgrains occurred in the strain rate range 0.01～1.0 s~(-1),and dynamic recovery ofβgrains predominates at 0.001 s~(-1).To obtain the desirable deformed microstructures,the optimum hot working conditions for TC11 alloy were found out in the temperature range 1 020～1 050℃and strain rate range 0.01～1.0 s~(-1).