焊后热处理对Al-Mg-Zn(-Sc-Zr)合金焊丝焊接7075铝合金焊接接头组织和性能的影响  

Effect of Post-weld Heat Treatment on Microstructure and Mechanical Properties of 7075 Alloy Welded by Al-Mg-Zn(-Sc-Zr) Alloy Welding Wire

作　　者：熊斯 唐鑫[1] 王春霞[1] 胡清华 XIONG Si;TANG Xin;WANG Chunxia;HU Qinghua(School of Materials Science and Engineering,Guilin University of Technology,Guilin 541004)

机构地区：[1]桂林理工大学材料科学与工程学院

出　　处：《材料导报》2019年第16期2720-2724,共5页Materials Reports

基　　金：广西科技重大专项(桂科AA17129005)~~

摘　　要：采用Al-Mg-Zn和Al-Mg-Zn-Sc-Zr合金焊丝为填充材料,对4 mm厚的7075-T651铝合金板材进行非熔化极惰性气体保护焊接(Tungsten inert gas welding,TIGW),并对焊接接头进行焊后热处理(Post-weld heat treatments,PWHT),研究焊接接头的显微组织和力学性能。结果表明,焊丝中添加微量Sc和Zr时,焊态下焊接接头的焊缝区晶粒明显得到细化,抗拉强度和硬度有明显提升;与未经PWHT的接头相比,经PWHT的接头弥散析出细小的η′(MgZn 2)亚稳定相,且并不影响二次Al 3(Sc,Zr)粒子的弥散分布,大幅度提高了焊接接头的抗拉强度和硬度。7075 aluminium alloy sheets of 4 mm thickness were welded by manual TIG welding method with Al-Mg-Zn and Al-Mg-Zn-Sc-Zr welding wires as filler material.Welded joints were treated by post-weld heat treatment(PWHT)method.The microstructure and mechanical properties of welded joints with and without post-weld heat treatment were investigated.The results showed that the grains of weld metal zone were refined and mechanical property of TIGW joint welded by Al-Mg-Zn-Sc-Zr welding wire was improved obviously.Compared with joint without post-weld heat treatment,the PWHT joint dispersed and precipitated with fineη′(MgZn 2)substable phase,which have no effect on the dispersion distribution of secondary Al 3(Sc,Zr)particles,and greatly improved the tensile strength and microhardness of the welded joint.

关 键 词：TIG焊 焊后热处理 微合金化 7075合金 

分 类 号：TG146.2[一般工业技术—材料科学与工程]