一种Al-Cu-Mg-Ag合金欠时效态的耐热性能  

Heat-Resistant Performance of an Underaged Al-Cu-Mg-Ag Alloy

作　　者：夏卿坤[1] 刘志义[1] 李云涛[1] 刘延斌[1] 周杰[1] 余日成[1] 

机构地区：[1]中南大学

出　　处：《稀有金属材料与工程》2007年第A03期608-611,共4页Rare Metal Materials and Engineering

基　　金：国家"973"重点基础研究发展项目(2005CB623705-04)

摘　　要：研究了欠时效态(165℃,2h)Al-Cu-Mg-Ag合金在热暴露、高温持久过程中组织与性能的变化。结果表明,试样在200℃,200 MPa高温持久下,随时间延长,其剩余强度先上升后下降,强度峰值出现在持久20 h。延伸率变化与强度变化基本相似。持久100 h后,合金力学性能相对欠时效态无明显下降,显示出优良的热稳定性;合金欠时效状态的组织为细小分布的Ω相,随着高温持久时间的延长,θ′相与Ω相竞争析出。无析出带(PFZ)逐渐增宽,同时发现晶界上有颗粒状析出物。在200℃热暴露下,其剩余强度的变化趋势与高温持久相同,但延伸率随时间延长而下降,其组织为过时效组织。The effects of thermal exposure and high temperature lasting on microstructure and mechanical properties of an underaged （165 ℃, 2 h）Al-Cu-Mg-Ag-Zr alloy have been investigated. The results show that with prolonging of lasting time, the residual stress of underageing samples appears to be increase first but then decrease, and the peaking stress is obtained when lasting for 20 h. The variation of ductility of the underageing samples has the same tendency with the variation of residual stress. Compared with underageing condition, the mechanical properties has no obvious variation after lasting for 100 h, which represents a superior heat-resistance ability. The fine and uniform distribution of Ω phase within the matrix grow and coarsen with prolonging of lasting time, and θ′ competitive precipitate and precipitate-free zone （PFZ） width increase. Compared with the high temperature lasting condition, the variation of strength of the underageing samples in exposure 200 ℃ has the same tendency, and the ductility decreases with prolonging of exposure time.

关 键 词：Al—Cu—Mg—Ag合金 热暴露 高温持久 显微组织 力学性能 

分 类 号：TG113.2[金属学及工艺—物理冶金]