预变形对2099合金组织性能的影响

Effect of Pre-stretch on Microstructure and Mechanical Properties of 2099 Alloy

通过显微硬度测试、力学性能测试和透射电镜观察等手段,研究了不同预变形程度对2099合金显微组织和力学性能的影响。结果表明,随着预变形程度增大,合金时效进程显著加快,合金峰时效态的强度显著提高;析出相更为细小弥散地分布于基体中,较为粗大的晶界析出相趋于不连续化、点链化;时效强化相经历了由T_1相、δ′相和θ′相三相共存到以T_1相为主要强化相的变化过程,表明预变形对时效过程中析出相的大小、类型、分布有重要影响,在促进T_1相析出的同时,也消耗了δ′相和θ′相。

Microstructure and mechanical properties of 2099 alloy under different pre-stretch degrees were studied by micro-hardening test, mechanical test and TEM observation. The results show that with the increase of pre-stretch the aging process is accelerated greatly and the mechanical properties are improved obviously. Precipitation phases become finer and more dispersed in the matrix, and some coarse phases in grain boundaries tend to be discontinuous and point chain. The main aging strengthening phases of 2099 alloy experience a transformation from three phases coexistence of T_1, δ′ and θ′ to T_1 phase. It indicates that pre-stretch has an important effect on the size, type and distribution of precipitation, which can promote T_1 phase precipitation in the expense of δ′ and θ′ phases consumption during the aging process.