(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 通過常規(guī)力學(xué)性能測試和透射電鏡微觀組織觀察，研究2099合金在不同熱處理狀態(tài)(T6和T8)下的微觀組織和拉伸性能，以及2099合金中所含少量Mg和Zn對合金組織與性能的影響。結(jié)果表明：2099合金在T6峰時效條件下，主要強(qiáng)化相是δ′相、θ′相和T1相；在T8峰時效下，主要強(qiáng)化相是δ′相、T1相和少量θ′相，預(yù)拉伸變形促進(jìn)T1相的析出，提高合金的時效強(qiáng)化效果；Mg的添加促進(jìn)GP區(qū)和θ′相的析出，Zn的添加有利于T1相生成和彌散分布；而Mg和Zn同時添加顯著地促進(jìn)T1相析出，并抑制δ′相的粗化。
關(guān)鍵字: 熱處理；拉伸性能；微觀組織；預(yù)拉伸變形；時效強(qiáng)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
