时效成形对7075铝合金焊接接头显微组织与力学性能的影响  

Effect of age forming on microstructure and mechanical properties of welded joint of 7075 aluminum alloy

作　　者：刘大海[1] 刘涛 邱全荣[1] LIU Da-hai;LIU Tao;QIU Quan-rong(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学航空制造工程学院

出　　处：《塑性工程学报》2020年第1期75-82,共8页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51375220);江西省省科技创新杰出青年人才培养计划资助项目(20192BCBL23002)

摘　　要：采用搅拌摩擦焊工艺(FSW)、时效成形试验、维氏硬度、金相观察和拉伸性能测试等方法研究了在180℃和不同时效时间下时效成形对7075铝合金FSW焊接接头显微组织与力学性能的影响。研究结果表明:随着时效时间的增加,母材区的第二相粒子逐渐减少,晶粒发生细化,热影响区与热机影响区的第二相粒子先增加后减少,在12 h时达到最多,焊核区的第二相粒子数量上无明显变化;抗拉强度与伸长率均先增大后减小,抗拉强度在12 h时达到最大,最大值为364. 15 MPa,伸长率在10 h达到最大值,最大值为3. 72%,拉伸断裂位置都在焊缝的前进侧。随着时效时间增加,各区硬度呈下降趋势,整体上母材区的硬度最高,热影响区的硬度最小,焊核区的硬度大小处于母材区与热影响区之间。The effects of age forming on the microstructures and mechanical properties of 7075 aluminium alloy friction stir welding( FSW) welded joints at 180 ℃ and different aging time were studied by using FSW process,age forming test,Vickers hardness test,metallographic observation and tensile property test. The results show that with the increase of aging time,the number of the second phase particles in base metal zone decreases gradually,grain refinement occurs,and the number of the second phase particles in heat-affected zone and heat engine-affected zone increases first,then decreases,and reaches the maximum at 12 h. The number of the second phase partides in the nugget zone changes little;the tensile strength and elongation increase first and then decrease,the tensile strength reaches the maximum at 12 h,with the maximum value of 364. 15 MPa,and the elongation reaches the maximum at 10 h,with the maximum value of 3. 72%. The tensile fracture locations are both at the front of the weld. With the increase of aging time,the hardness of the zones shows the trend of decrease,on the whole,the hardness of base metal zone is the highest,and the hardness of heat-affected zone is the smallest,and the hardness of nugget zone is between that of base metal zone and heat-affected zone.

关 键 词：7075铝合金 时效成形 搅拌摩擦焊 微观组织 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]