热暴露对Al-Cu-Mg-Ag合金组织和性能的影响  

Effect of thermal exposure on the microstructure and properties of Al-Cu-Mg-Ag alloy

作　　者：夏卿坤[1] 刘志义[1] 李云涛[1] 胡冠昱[2] 刘延斌[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]长沙学院机电工程系,长沙410003

出　　处：《北京科技大学学报》2008年第6期625-629,663,共6页Journal of University of Science and Technology Beijing

基　　金：国家重点基础研究发展计划资助项目(No.2005CB623705-04)

摘　　要：研究了Al—Cu—Mg—Ag合金经时效处理165℃×2h（欠时效态）后，在不同温度（150～300℃）和不同时间（0～1000h）热暴露后的显微组织和性能．结果表明：在150℃热暴露下，随时间延长，其剩余强度先上升后下降，强度峰值出现在100h。在1000h后合金力学性能相对欠时效态无明显下降；在200～300℃热暴露时，合金的强度随时间的延长而下降，延伸率随着时间的延长而增大；在300℃热暴露时，合金的强度明显下降，暴露10h后其抗拉强度为272．5MPa，100h后其抗拉强度降至114．5MPa．欠时效状态的合金组织主要为均匀细小分布Ω相；随着暴露温度的升高，Ω相长大并粗化，晶界无析出带（PFZ）变宽．The microstructure and mechanical properties of an Al-Cu-Mg-Ag alloy aged at 165 ℃ were investigated, and the underage （165 ℃ × 2 h） samples were subjected to thermal exposure at 150, 200, 250 and 300 ℃ for 0 to 1000 h. The results indicate that at the exposure temperature of 150 ℃, the residual strength of underage samples appears to increase first and then decrease, and the peaking strength is obtained when lasting for 100 h. The change in elongation of the samples has the same tendency as the change in residual strength. Compared with underage condition, the mechanical properties of the samples have no obvious variation after the 150 ℃/1000 h exposure, and thus the alloy represents a superior heat-resistance ability. With prolonging exposure time and increasing temperature, the residual strength of the samples appears to decrease and the elongation appears to increase at 200, 250, and 300℃ . The residual strength of the samples obviously decrease at the exposure temperature of 300 ℃, and the tensile strength of the samples after the 10 h exposure is 272.5 MPa decreasing to 114.5 MPa after the 100 h exposure. At all examined temperatures the Ω plate thickening shows a linear dependence on time. With increasing exposure temperature, the Ω plate thickening kinetics greatly increases and the precipitation free zones broaden in grain boundary.

关 键 词：铝合金 欠时效 热暴露 显微组织 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]