脉冲磁场频率对铝/钢CMT熔钎焊接头组织及性能的影响

Effect of Pulsed Magnetic Field Frequency on Microstructure and Properties of Al Alloy/steel CMT Welding-brazing joint

中文关键词: CMT熔钎焊  脉冲磁场  铝/钢异种金属  微观组织  腐蚀性能

英文关键词: CMT welding-brazing  pulsed magnetic field  Al/steel dissimilar metals  microstructure  corrosion resistance

中文摘要:

      目的 研究不同脉冲磁场频率对铝/钢焊接接头结合质量的影响，实现铝/钢异种金属的高效焊接。方法 采用脉冲磁场辅助CMT熔钎焊方法，对6061铝合金试板和Q235B钢板进行对接焊，通过光学显微镜、扫描电子显微镜和万能力学试验机等设备对铝/钢接头微观组织、力学性能和耐腐蚀性能进行分析。结果 添加脉冲磁场后没有改变焊接接头的组织构成，焊缝主要由Al-Si共晶组织和α-Al固溶体构成。铝/钢界面层由θ-Fe2(Al, Si)5和τ5-Al7.2Fe1.8Si组成。随着脉冲磁场频率的增加，焊缝组织晶粒尺寸发生细化，当脉冲磁场频率为20 Hz时，Al-Si共晶组织尺寸最小。此时，接头的平均抗拉强度最大，为193.5 MPa。脉冲磁场频率大小对铝/钢接头耐腐蚀性能有一定影响。随着脉冲磁场频率的增加，接头的耐腐蚀性先升高后降低。当磁场频率为20 Hz时，铝/钢接头耐腐蚀性能最好。其实质是脉冲磁场频率影响界面层的IMC厚度，最终抑制了接头的电偶腐蚀。结论 脉冲磁场频率大小可以影响铝/钢界面IMC层的厚度，添加合适的磁场频率可以进一步提高铝/钢界面的结合质量，接头的抗拉强度和耐腐蚀性均能得到提高。

英文摘要:

      The work aims to study the effect of different pulse magnetic field frequencies on the interface bonding quality of aluminum/steel welded joints, and realize efficient welding of aluminum/steel dissimilar metals. The butt welding of 6061 aluminum alloy test plates and Q235B steel plates was carried out by pulsed magnetic field assisted CMT welding-brazing method. The microstructure, mechanical properties and corrosion resistance of aluminum/steel joints were analyzed by optical microscope, scanning electron microscope and universal mechanical testing machine. The microstructure of the welded joint was not changed after adding the pulsed magnetic field. The weld was mainly composed of Al-Si eutectic structure and α-Al solid solution. The Al/steel interface layer was composed of θ-Fe2(Al, Si)5 and τ5-Al7.2Fe1.8Si. As the frequency of the pulsed magnetic field increased, the grain size of the weld microstructure was refined. When the pulsed magnetic field frequency was 20 Hz, the size of the Al-Si eutectic structure was the smallest. At this time, the average tensile strength of the joint was 193.5 MPa. The pulsed magnetic field frequency affected the corrosion resistance of aluminum/steel joints. With the increase of the pulsed magnetic field frequency, the corrosion resistance of the joint increased first and then decreased. When the magnetic field frequency was 20 Hz, the corrosion resistance of the aluminum/steel joint was the best. The essence was that the pulsed magnetic field frequency affected the IMC thickness of the interface layer, and ultimately inhibited the galvanic corrosion of the joint. The frequency of the pulsed magnetic field can affect the thickness of the IMC layer at the aluminum/steel interface. Adding a suitable magnetic field frequency can further improve the bonding quality of the aluminum/steel interface, and the tensile strength and corrosion resistance of the joint can be improved.