Al-Cu-Mg-Ag耐热铝合金的热稳定性  

Thermal stability of Al-Cu-Mg-Ag heat-resistant alloy

作　　者：刘晓艳[1] 潘清林[1,2] 陆智伦[1] 曹素芳[1] 何运斌[1] 李文斌[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083

出　　处：《中国有色金属学报》2011年第6期1244-1251,共8页The Chinese Journal of Nonferrous Metals

基　　金：国防科工委军品配套研制项目(JPPT-115-2-948);中南大学优秀博士学位论文扶植基金资助项目(2008yb012)

摘　　要：采用力学拉伸性能测试和透射电镜微观组织观察,分析欠时效态和峰时效态Al-Cu-Mg-Ag合金的热稳定性,并研究热暴露温度和时间对合金组织与力学性能的影响。结果表明:在150℃下,欠时效态合金的稳定性能明显优于峰时效态合金的;峰时效态合金的抗拉强度随着热暴露时间的延长逐渐减小,合金中的强化相-相和少量的θ′相逐渐发生粗化;欠时效态合金的抗拉强度随热暴露时间的延长先增大后减小,合金组织中的析出相数量先增多后减少,并发生粗化;热暴露20 h后,欠时效态合金的抗拉强度达到峰值524 MPa,比峰时效态合金的强度高19 MPa;此时,合金组织中的-相呈弥散分布,并且出现大量细小的θ′相;欠时效态合金在150℃下热暴露1 000 h后,其抗拉强度减小为434 MPa,仍能达到峰时效态合金的86%;当热暴露温度升高至200℃时,随热暴露时间的延长,欠时效态合金的抗拉强度减小,伸长率增大;热暴露1 000 h后,其抗拉强度降低到307 MPa;在250和300℃下热暴露时,欠时效态合金的抗拉强度随时间的延长急剧减小,组织中的强化相数量明显减少,并逐步演变成粗大的平衡相θ相。The thermal stability of Al-Cu-Mg-Ag alloys under-aged and peak-aged was analyzed by tensile test and transmission electron microscopy（TEM）.And the effects of thermal exposure temperature and holding time on the microstructure and mechanical properties of Al-Cu-Mg-Ag alloy were also studied.The results show that the thermal stability of the under-aged Al-Cu-Mg-Ag alloy is superior to that of the peak-aged alloy when exposed at 150 ℃.The tensile strength of the peak-aged alloy decreases with prolonging the holding time.And the strengthening phases Ω and little θ′ are coarsened gradually.The tensile strength of the under-aged alloy increases and then decreases with prolonging the time.And the number of the precipitations increases and then decreases with the slowly coarsening of the precipitations.The tensile strength of Al-Cu-Mg-Ag alloy reaches the peak value of 524 MPa after exposed for 20 h,which is 19 MPa larger than that of the peak-aged alloy.Meanwhile the precipitations Ω distribute dispersively and a large amount of fine θ′ phase is observed.The tensile strength of the under-aged alloy is 434 MPa after exposed at 150 ℃ for 1 000 h,which is 86% of that of the peak-aged alloy.When exposed at 200 ℃,the tensile strength decreases and the prolongation increases with prolonging the exposure time.The tensile strength decreases to 307 MPa after exposed for 1 000 h.The tensile strength decreases dramatically with prolonging the holding time.And the number of the strengthening phases decreases obviously and grows to equilibrium phase θ.

关 键 词：AL-CU-MG-AG合金 热暴露 欠时效 力学性能 显微组织 

分 类 号：TG146.21[一般工业技术—材料科学与工程]