锌夹层添加对镁-铝异种金属搅拌摩擦点焊接头组织与性能的影响

发布时间：2018-02-11 18:13

本文关键词： 异种金属搅拌摩擦点焊锌夹层金属间化合物　出处：《机械工程学报》2017年04期 　论文类型：期刊论文

【摘要】：对于镁-铝异种金属的搅拌摩擦点焊(Friction stir spot weld,FSSW),镁-铝界面处连续分布的脆性Mg-Al金属间化合物是影响其强度的关键因素。针对AZ31镁合金和2024铝合金薄板的FSSW,采用0.1 mm厚纯锌箔作为预置夹层,分析锌夹层添加对接头微观组织与力学性能的影响。结果表明,无夹层时,接头中仅在钩状区中的镁-铝界面处生成了厚度约为5μm的连续金属间化合物层,其余部分以机械结合为主,接头拉剪载荷仅为0.8 k N。锌夹层添加后,降低了钩状区中靠近匙孔一侧的过渡层厚度(约2μm),并使钩状区外侧界面处生成了新型Al-Zn、Zn-Mg化合物组织,起到了阻碍该区域Mg-Al金属间化合物生成的作用,达到了促进镁、铝之间冶金结合的效果。与无夹层相比,有夹层接头拉剪载荷提高了75%,达到1.4 k N。
[Abstract]:For friction stir friction stir spot welding of magnesium-aluminum dissimilar metals, the brittle Mg-Al intermetallic compounds distributed continuously at the magnesium-aluminum interface are the key factors affecting the strength of FSSWs. For AZ31 magnesium alloy and 2024 aluminum alloy sheet FSSW, the FSSWs of AZ31 magnesium alloy and 2024 aluminum alloy sheet are adopted. Mm thick pure zinc foil as preset interlayer, The effect of zinc intercalation on the microstructure and mechanical properties of joints is analyzed. The results show that, without the interlayer, a continuous intermetallic layer of about 5 渭 m thick is formed at the interface between magnesium and aluminum in the hook zone. The rest of the joints are mainly mechanically bonded, and the tensile shear load of the joints is only 0.8 kN. after the addition of the zinc interlayer, the thickness of the transition layer near the keyhole side in the hook zone is reduced (about 2 渭 m), and a new type of Al-ZnZn-Mg compound structure is formed at the outer interface of the hook zone. It has the effect of hindering the formation of Mg-Al intermetallic compounds in this region and promoting the metallurgical bonding between magnesium and aluminum. Compared with no intercalation, the tensile and shear loads of the sandwich joints are increased by 75% to 1.4 KN.
【作者单位】：沈阳航空航天大学材料科学与工程学院;中国科学院金属研究所;
【分类号】：TG456

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