(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 通过常规力学性能测试和透射电镜微观组织观察，研究2099合金在不同热处理状态(T6和T8)下的微观组织和拉伸性能，以及2099合金中所含少量Mg和Zn对合金组织与性能的影响。结果表明：2099合金在T6峰时效条件下，主要强化相是δ′相、θ′相和T1相；在T8峰时效下，主要强化相是δ′相、T1相和少量θ′相，预拉伸变形促进T1相的析出，提高合金的时效强化效果；Mg的添加促进GP区和θ′相的析出，Zn的添加有利于T1相生成和弥散分布；而Mg和Zn同时添加显著地促进T1相析出，并抑制δ′相的粗化。
关键字: 热处理；拉伸性能；微观组织；预拉伸变形；时效强化
tensile properties of 2099 alloy
（School of Materials Science and Engineering, Central South University, Changsha 410083，China）
Abstract:The tensile properties and microstructure of 2099 alloy in T6 and T8 tempers were investigated by tensile test and TEM observation. Moreover, the effects of the Mg and Zn in 2099 alloy on the microstructure and properties of alloy were studied. The results show that under T6 peak aged condition, the dominant precipitates are δ′, θ′ and T1 phases. While under T8 peak aged condition, the major precipitates contain δ′ phase, T1 phase and θ′ phase with small volume fractions. The pre-stretching prior to ageing promotes the precipitation of T1 phase, thus improves ageing strengthening. Mg addition promotes the precipitation of GP zone and θ′ phase while Zn facilitates T1 phase precipitation. The addition of Mg together with Zn stimulates the formation of T1 phase obviously, and suppresses the coarsening progress of δ′ phase.
Key words: heat treatment; tensile properties; microstructure; pre-stretching; ageing strengthening
