固溶时效处理对7A52铝合金CMT+P焊接接头组织及性能的影响  

Effect of Solution Aging Treatment on Microstructure and Properties of 7A52 Aluminum Alloy CMT+P Welded Joint

作　　者：刘洪旭 王艳杰 刘峰[1] 赵琳[2] 田志凌[2] Liu Hongxu;Wang Yanjie;Liu Feng;Zhao Lin;Tian Zhiling(College of Mechanical Engineering,Liaoning University of Petrochemical Technology,Fushun 113001,China;Welding Institute of General Iron and Steel Research Institute,Beijing 100081,China;College of Material Engineering,Beihua Institute of Aerospace Engineering,Langfang 065000,China)

机构地区：[1]辽宁石油化工大学机械工程学院,辽宁抚顺113001 [2]钢铁研究总院焊接所,北京100081 [3]北华航天工业学院材料工程学院,河北廊坊065000

出　　处：《稀有金属材料与工程》2023年第5期1905-1914,共10页Rare Metal Materials and Engineering

基　　金：国防基础科研项目(JCKY2018512B001)。

摘　　要：采用冷金属过渡+脉冲焊接(CMT+P)方法对7A52铝合金进行焊接实验,研究不同热处理工艺对焊接接头显微组织及力学性能的影响。结果表明,焊缝区由树枝晶或等轴树枝晶为主的显微组织经热处理后均已转变为等轴晶,但AA(人工时效)试样的晶粒组织和第二相尺寸更加粗大且晶界存在偏析现象。T6(固溶+人工时效)试样的焊缝区析出相数量多于AA试样,而且热影响区的η’(MgZn_(2))强化相尺寸以及无沉淀析出带宽度均减小。AA和T6试样的接头强度分别达到315和356MPa,AA试样对接头力学性能提升有限,T6试样相比于AW(焊态)试样提高了约14.10%,AA试样的微观断口主要表现为韧窝型穿晶断裂,而T6试样断口中的韧窝数量明显减少,取而代之是无特征的平台,此时接头以穿晶+沿晶的韧脆混合断裂为主。Cold metal transfer+pulse welding(CMT+P)method was used to weld 7A52 aluminum alloy,and the effects of different heat treatment processes on the microstructure and mechanical properties of welded joints were studied.The results show that the microstructure dominated by dendrite or equiaxed dendrite in the weld zone is transformed into equiaxed crystal after heat treatment,the grain structure and the size of the second phase of AA(artificial aging)sample are coarser,and there is segregation at the grain boundary.The amount of precipitates in T6(solid solution+artificial aging)weld zone is more than in AA sample,and the size ofη′(MgZn_(2))strengthening phase and the width of precipitation free zone decrease in the heat affected zone.The joint strength of AA and T6 samples reaches 315 and 356 MPa,respectively.AA sample has limited improvement on the mechanical properties of the joint,while T6 sample is increased by about 14.10%compared with AW sample(312 MPa).The micro fracture of AA sample is mainly dimple transgranular fracture,while the number of dimples in the fracture of T6 sample is significantly reduced and replaced by an uncharacteristic platform.At this time,the joint is mainly transgranular+intergranular ductile brittle mixed fracture.

关 键 词：CMT+P焊接 7A52铝合金 固溶时效 显微组织 力学性能 

分 类 号：TG456[金属学及工艺—焊接] TG146.21[一般工业技术—材料科学与工程]