摘要
基于显微组织表征和等温热模拟压缩试验,研究TC17 合金在α+β两相区变形时的显微组织演变及其对流动应力的影响。研究表明:当变形温度为820 和850℃时,随着应变的增加,α相的球化率略微增加;随着变形温度的升高,α相的球化率略微增加,但是α相的体积分数明显减小。当变形温度为780℃、应变速率为1 s^-1 时,流动应力呈减小趋势;当应变为1.2 时,由于位错湮没和α片层转动,流动应力未达到稳定状态。当变形温度为820 和850℃、应变速率为1 s^-1、应变大于0.8 时,由于加工硬化和动态软化的平衡作用,流动应力呈稳定状态。合金动态软化归因于α片层转动、动态回复和轻微的球化。
The microstructure evolution and its effect on flow stress of TC17 alloy during deformation in the α+β two-phase region were investigated via microstructure characterization and isothermal compression tests. Results showed that the spheroidized rate of α phase at 820 and 850℃ slightly increased with increasing strain. With increasing deformation temperature, the spheroidized rate of α phase showed a slight increasing trend, but the volume fraction of α phase significantly decreased. The flow stress at 780 ℃ and 1 s^-1 decreased continuously and steady state condition was not achieved up to strain of 1.2 due to dislocation annihilation and α lamellae rotation. Under this condition, the dynamic spheroidization was retarded. At the deformation temperatures of 820 and 850℃, and a strain rate of 1 s^-1, a steady state flow stress was observed at strains above 0.8 due to the balance between work hardening and dynamic softening. The dynamic softening was attributed to the α lamellae rotation, dynamic recovery and a little spheroidization.
作者
罗皎
叶鹏
韩文超
李淼泉
Jiao LUO;Peng YE;Wen-chao HAN;Miao-quan LI(School of Materials Science and Engineering,Northwestern Polytechnical University,Xi’an 710072,China)
基金
Project(51575446)supported by the National Natural Science Foundation of China
Project(2017KJXX-27)supported by the Shaanxi Province Youth Science and Technology New Star Plan,China
Project(3102017AX003)supported by the Fundamental Research Funds for the Central Universities,China
关键词
TC17合金
球化率
显微组织演变
流动应力
显微组织表征
TC17 alloy
spheroidized rate
microstructure evolution
flow stress
microstructure characterization