应力对2198铝锂合金板材人工时效的影响  

Effect of stress on artificial aging of 2198 Al-Li alloy sheet

作　　者：尹延广 李丰 张帅[2] 樊智贤 陈宏燃 赵天章[1] YIN Yanguang;LI Feng;ZHANG Shuai;FAN Zhixian;CHEN Hongran;ZHAO Tianzhang(Faculty of Aerospace Engineering,Shenyang Aerospace University,Shenyang 110136,China;Shenyang Aircraft Corporation,Shenyang 110034,China)

机构地区：[1]沈阳航空航天大学航空宇航学院,辽宁沈阳110136 [2]沈阳飞机工业(集团)有限公司,辽宁沈阳110034

出　　处：《兵器材料科学与工程》2022年第4期29-34,共6页Ordnance Material Science and Engineering

基　　金：国家自然科学基金青年项目(51605310);辽宁省教育厅项目(LJKZ0180);沈阳市中青年科技创新人才支持计划(RC210422)。

摘　　要：用单向拉伸分别测试经145℃和165℃的人工时效和应力松弛时效的2198铝锂合金板材沿RD方向的室温力学性能,通过透射电子显微镜观察不同热处理状态下时效相的形貌。结果表明:145℃人工时效后,未析出T相,未发生δ’相回溶,但时效过程中应力的引入导致δ’相数量骤减,屈服强度下降,伸长率上升。经165℃人工时效后,基体中析出了少数T相,并出现明显δ’相回溶,屈服强度和伸长率同时下降,但应力松弛时效后,δ’相数量进一步减少,直径明显下降,取而代之的是大量T相,直径降低且分布均匀,屈服强度大幅提高。因此,应力对2198铝锂合金板材人工时效的影响主要包含两个方面:加速δ’相回溶;促进T_(1)相析出。The mechanical properties at room temperature of 2198 Al-Li alloy sheet along RD subjected to artificial aging and stress relaxation aging at 145 ℃ and 165 ℃ were tested using uniaxial tension. The precipitate morphology at different heat treatment states were observed by transmission electron microscopy. The results show that there is not any Tphase after artificial aging at 145 ℃ and δ’ phase does not dissolve back. However,the exerted stress during artificial aging leads to a much decrease of the number of δ’ phase,resulting in a decrease of yielding strength and an increase of elongation. After artificial aging at165 ℃,a few Tphases precipitate in the matrix and δ’ phases dissolve. Therefore,the yielding strength and elongation decrease at the same time. However,after stress relaxation aging,the number and the diameter of δ’ phase decrease significantly. It is replaced by a large number of Tphases with smaller diameter and more uniform distribution,resulting in a substantial increase in yielding strength. Therefore,stress during the artificial aging of 2198 Al-Li alloy sheet has two main influences on the precipitation:Accelerating the dissolution of the δ’ phase and promoting the precipitation of the T_(1) phase.

关 键 词：2198铝锂合金 热处理 应力松弛时效 时效相 

分 类 号：TG146.21[一般工业技术—材料科学与工程]