摘要
【目的】采用预置Ni/Zn中间层的方法进行Q355钢/6061铝合金异种金属的电阻点焊研究。【方法】在不同焊接时间、焊接电流及电极压力下分别对6061铝合金与Q355钢的电阻点焊工艺进行对比分析并获得最优电阻点焊工艺参数,然后采用在铝合金板与钢板之间添加Ni/Zn箔片作为中间层的方法来研究Ni/Zn中间层对铝/钢电阻点焊接头组织与性能的影响,并利用光学显微镜、扫描电镜、能谱分析及拉伸试验机等方法对含Ni/Zn中间层的铝/钢电阻点焊接头微观组织、元素占比、第二相的变化及抗拉剪力进行了研究。【结果】结果表明,铝/钢点焊接头由铝一侧熔核,钢一侧熔核和结合界面处的金属间化合物组成,具有典型的双熔核特征。通过在6061铝合金与Q355钢的中间分别增加Ni与Zn箔片来阻碍脆硬的Al-Fe金属间化合物的生成量。添加Ni中间层的接头界面区生成了韧性较好的Al3Ni,从而阻碍了硬而脆的Al-Fe金属间化合物的形成。添加Zn中间层的接头界面区生成了一定量的Fe2Al5Zn0.4,使Al-Fe金属间化合物层的厚度减小至2.88μm,最大抗拉剪力达到4.69 kN。【结论】添加Ni/Zn中间层后,铝/钢电阻点焊接头的熔核直径与抗拉剪力均有所提升,同时Ni元素的添加会在铝/钢界面处生成韧性较好的Al3Ni相,从而阻碍了Al-Fe金属间化合物的生成。
[Objective]Resistance spot welding of Q355 steel/6061 aluminum alloy was studied by presetting Ni/Zn interlayer.[Methods]Under different welding time,welding current and electrode pressure,resistance spot welding process of 6061 aluminum alloy and Q355 steel was compared and analyzed,and the optimal resistance spot welding parameters were obtained.Then,by adding Ni/Zn foil between aluminum alloy plate and steel plate,effect of Ni/Zn interlayer on microstructure and properties of aluminum/steel resistance spot welded joints was studied.Microstructure,element proportion,change of second phase and tensile-shear force of aluminum/steel resistance spot welded joints with Ni/Zn interlayer were studied by means of optical microscope,scanning electron microscope,energy spectrum analysis and tensile testing machine.[Results]The results showed that aluminum/steel spot welded joints were composed of nugget on the side of aluminum,nugget on the side of steel and intermetallic compounds at the bonding interface,which had typical characteristics of double nuggets.Adding Ni and Zn foil to the middle between 6061 aluminum alloy and Q355 steel separately hindered the formation of brittle Al-Fe intermetallic compounds.The addition of Ni interlayer led to the formation of a better ductile Al3Ni at the interface of welded joints,thereby hindering the formation of hard and brittle Al-Fe intermetallic compounds.The addition of Zn interlayer generated a certain amount of Fe2Al5Zn0.4 at the interface of welded joints,which reduced the thickness of Al-Fe intermetallic compounds layer to 2.88μm,and achieved the maximum tensile-shear force of 4.69 kN.[Conclusion]After the addition of Ni/Zn interlayer,nugget diameter and tensile-shear force of aluminum/steel resistance spot welded joints increased,and the addition of Ni element would generate Al3Ni phase with good toughness at the aluminum/steel interface,thus hindering the formation of Al-Fe intermetallic compounds.
作者
陈芙蓉
张正
李汶轩
李建军
樊宇峰
Chen Furong;Zhang Zheng;Li Wenxuan;Li Jianjun;Fan Yufeng(School of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China)
出处
《焊接》
2024年第11期46-53,共8页
Welding & Joining
基金
内蒙古自治区研究生科研创新资助项目(RZ2300001797)。
