Al-6.6Zn-1.7Mg-0.26Cu合金MIG焊接接头的显微组织与力学性能
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摘要
采用维氏硬度仪、拉伸试验机、光学显微镜、扫描电镜和透射电镜,研究了Al-6.6Zn-1.7Mg-0.26Cu合金挤压材熔化极惰性气体保护焊接头的显微组织和力学性能。结果表明,焊缝中心区为枝晶组织,焊缝靠近母材侧的熔合区为柱状晶组织,母材为等轴晶组织,但靠近焊缝熔合区的母材晶粒发生了长大。焊接接头的硬度值以焊缝为中心呈对称分布,从母材到焊缝中心,硬度先下降后上升再下降,焊缝中心区的硬度最低。接头的抗拉强度为309 N/mm~2,屈服强度为236.5 N/mm~2,伸长率为4.75%,挤压材的焊接强度系数为0.76。
The microstructure and mechanical properties of MIG welded joint of the as-extruded Al-6.6Zn-1.7Mg-0.26Cu alloy were investigated by the vickers hardness tester,the tensile tester,the optical microscope,the scanning electron microscope and the transmission electron microscope.The results show that the welded zone center is the dendrite structure,the fusion zone near the base is the columnar crystal structure,the base is the equiaxed grain structure,but the grain size of the base near the welded fusion zone becomes bigger.The hardness value of the welded joint is symmetrically distributed around the center of the weld.The hardness decreases,rises and then decreases from the base to the weld center,with the lowest point in the center.The tensile strength,the yield strength and the elongation of the welded joint are 309 N/mm~2,236.5 N/mm~2 and 4.75%,respectively.0.76 is the welding strength coefficient of the as-extruded Al-6.6Zn-1.7Mg-0.26Cu alloy.
The microstructure and mechanical properties of MIG welded joint of the as-extruded Al-6.6Zn-1.7Mg-0.26Cu alloy were investigated by the vickers hardness tester,the tensile tester,the optical microscope,the scanning electron microscope and the transmission electron microscope.The results show that the welded zone center is the dendrite structure,the fusion zone near the base is the columnar crystal structure,the base is the equiaxed grain structure,but the grain size of the base near the welded fusion zone becomes bigger.The hardness value of the welded joint is symmetrically distributed around the center of the weld.The hardness decreases,rises and then decreases from the base to the weld center,with the lowest point in the center.The tensile strength,the yield strength and the elongation of the welded joint are 309 N/mm~2,236.5 N/mm~2 and 4.75%,respectively.0.76 is the welding strength coefficient of the as-extruded Al-6.6Zn-1.7Mg-0.26Cu alloy.
引文
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[3]宋冰.7003铝合金汽车保险杠型材生产工艺的研究[J].冶金丛刊,2016(2):16-20.
[4]商宝川,尹志民,周向,等.固溶-时效对Al-Zn-Mg-Sc-Zr合金板材组织与性能的影响[J].中国有色金属学报,2010,20(11):2063-2069.
[5]商宝川,尹志民,周向,等.固溶-时效对Al-Zn-Mg-Sc-Zr合金板材组织与性能的影响[J].中国有色金属学报,2010,20(11):2063-2069.
[6]HASANNEJAD H,SHAHRABI T,ALIOFKHAZRAEI M.Effects of acetic acid on microstructure and electrochemical properties of nano cerium oxide films coated on AA7020-T6 aluminum alloy[J].Rare Metals,2009,28(1):98-101.
[7]金龙兵,赵刚,冯正海,路丽英.高速列车用中强可焊AI-Zn-Mg合金材料[J].轻合金加工技术,2010,38(12):47-51.
[8]彭小燕,曹晓武,段雨露,等.7020铝合金MIG焊焊接接头的组织与性能[J].中国有色金属学报,2014,24(4):912-918.
[9]章友谊,刘华,朱小兵.7A52铝合金MIG焊焊接接头显微组织与性能研究[J].热加工工艺,2013(19):172-174.
[10]周友龙,张力,陈舟,等.7020铝合金搅拌摩擦焊与MIG焊接对比试验[J].电焊机,2011,41(11):91-94.
[11]许瑞麟,朱品朝,于成哉,等.汽车车身焊接技术现状及发展趋势[J].电焊机,2010,40(5):1-18.
[12]DUDZIK K.Influence of joining method for hardness distribution in joints of Al ZnSMg1 alloy[J].Journal of KONES,2010,17:137-141.
[13]ARES A E,GUEIJMAN S F,CARAM R,et al.Analysis of solidification parameters during solidification of lead and aluminum base alloys[J].Journal of Crystal Growth,2005,275(1/2):319-327.
[14]李慧中,郭菲菲,梁霄鹏,等.焊丝成分对2519铝合金焊缝组织与性能的影响[J].焊接学报,2008,29(4):77-81.
[15]许良红,田志凌,彭云,等.微量元素对高强铝合金焊缝组织和力学性能的影响[J].中国有色金属学报,2008,18(6):959-966.
[16]QUEUDET H,LEMONNIER S,BARRAUD E,et al.Effect of heat treatments on the microstructure of an ultrafine-grained Al-Zn-Mg alloy produced by powder metallurgy[J].Materials Science&Engineering A,2016,685:71-78.