Hastelloy C-276合金高温压缩的动态再结晶行为

Dynamic recrystallization behavior of hastelloy C-276 superalloy during hot compression tests

在Gleeble-3500热模拟机上对Hastelloy C-276(C-276)合金在变形温度为1 000~1 250℃和应变速率为0.01~10.00s^(-1)的变形条件下进行了高温压缩试验,研究了C-276合金热变形过程中组织演变和动态再结晶行为。结果表明,随着变形温度的升高,动态再结晶晶粒尺寸增大,动态再结晶进行得越充分;随着变形程度的增加,动态再结晶体积分数增大,动态再结晶晶粒略有长大;该合金发生动态再结晶的临界应变ε_c与Z参数和ε_p之间的关系分别为:ε_c=7.67×10^(-4)Z^(0.144),ε_c≈0.78ε_p;该合金动态再结晶形核机制主要为晶界弓弯形核机制,也存在孪生诱发动态再结晶形核机制。C-276合金热变形过程中晶粒得到显著细化,组织的均匀性得到有效改善,选用适宜的热加工工艺,可以获得细小均匀的组织。

Microstructural evolution deformation of C-276 superalloy were inve and dynamic recrystallization behavior during hot stigated by means of hot compression tests in the temperature range of 1 000 - 1 250 ℃ and strain rate range of 0.01 - 10.00 s^ -1 on Gleeble 3500 simulator. The results showed that the dynamic recrystallization（DRX） grain size increased and DRX was developed enough with increasing temperature. DRX volume fraction increased and DRX grain was slight growth with the increase of strain. recrystallization εc with Zener-Hollomon parameter The relationship of critical strain of dynamic and εp can be expressed as εo =7.67 × 10^-4Z^0.144 and εc ≈ 0. 78εp. The DRX nucleation mechanism was mainly with grain boundary bowing nucleation mechanism and also with twinning induced dynamic recrystallization nucleation mechanism. The C-276 superalloy grain was significantly refined and the mierostructural homogeneity was improved effectively during hot deformation. The refined and uniform grains were obtained by the selection of suitable thermal processing parameters.