摘要
采用Gleeble-1500热模拟机在变形温度为1000～1150℃、应变速率为10-3～100s-1的变形条件下,研究Ti-47Al-2Cr-0.2Mo(摩尔分数,%)合金的热变形行为。利用光学显微镜和扫描电子显微镜分析合金在不同变形条件下的组织演化规律。结果表明:流变应力随着应变速率提高和变形温度降低而增大;在变形过程中,流变应力随着变形量增大而增大,当流变应力达到峰值后趋于平稳,表明合金在变形过程中发生了动态再结晶;热变形过程的流变应力可采用双曲正弦本构关系来描述,平均激活能为337.75kJ/mol;从合金的组织演化过程中可以看出,合金中不均匀的原始组织得到明显均匀化,变形后的组织是由α2/γ层片晶团和γ晶粒组成的双态组织,在α2/γ层片晶团和γ晶粒的晶界交界处发现分布均匀的B2相,并且随着变形温度升高B2相数量逐渐减少。
The hot deformation behaviors of the Ti-47Al-2Cr-0.2Mo （mole fraction, %） alloy were studied with a Gleeble-1500 machine at 1 000-1 150 ℃ with the strain rate of 10-3-100 s-1. The microstructural evolution of the alloy was investigated by optical microscopy and scanning electron microscopy. The results indicate that the flow stress of the alloy increases with increasing strain rate and decreasing deformation temperature. The flow stress increases with increasing strain until the stress reaches the peak value, then the flow stress remains constant, which indicates that dynamic recrystallization happens during deformation. The flow behaviors are described by the hyperbolic sine constitutive equation, and the activation energy calculated is 337.75 kJ/mol. The as-forged microstructure consists of refmed α2/γ and γ, grains, and the grains are much homogeneous than before. The B2 phase distributes uniformly at the grain boundary of α2/γand γ, grains. The B2 phase decreases with increasing deformation temperature.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2010年第1期79-85,共7页
The Chinese Journal of Nonferrous Metals
基金
国家高技术研究发展计划资助项目(2008AA03A233)
中国博士后基金资助项目(20070420828)
中南大学博士后基金资助项目(2008-8)
关键词
TIAL基合金
热变形
流变应力
动态再结晶
激活能
B2相
TiAl based alloy
hot deformation
flow stress
dynamic recrystallization
activation energy
B2 phase
