【摘要】 【目的】旨在改善铝/钢异种金属焊接接头的界面结合强度与耐腐蚀性能，探究脉冲磁场在冷金属过渡（Cold metal transfer, CMT）熔钎焊中对接头组织与性能的作用机制。【方法】在CMT熔钎焊中引入脉冲磁场，采用ER4047F药芯焊丝，对2 mm厚6061铝合金与Q235B钢进行对接试验，对比有无磁场条件下接头宏观形貌、微观组织、力学性能及腐蚀性能的差异。【结果】结果表明，脉冲磁场显著提升焊缝润湿铺展性，获得成形饱满、冶金结合面更大的接头；磁场不改变金属间化合物（Intermetallic compound, IMC）层主要成分，可抑制Fe元素扩散，降低脆性Fe-Al IMC层厚度，并通过电磁搅拌使IMC层呈波浪状、晶粒细化，界面结合强度较无磁场时提升49.9%；电化学测试表明，脉冲磁场通过控制IMC层厚度抑制电偶腐蚀，同时细化晶粒阻碍腐蚀介质沿晶界扩散与侵蚀。【结论】脉冲磁场能有效优化铝/钢CMT熔钎焊接头组织形貌，提升界面结合强度与耐腐蚀性，为铝/钢异种材高质量焊接提供可行调控方法。更多还原

【Abstract】 [Objective] The aim is to improve interfacial bonding strength and corrosion resistance of Al/steel dissimilar metal welded joints,and to explore mechanism of pulsed magnetic field on microstructure and properties of the joints during cold metal transfer(CMT) weldingbrazing. [Methods] Pulsed magnetic field was introduced into CMT welding-brazing. ER4047F flux-cored wire was used as filler metal to butt2 mm-thick 6061 aluminum alloy and Q235B steel. Macro morphology, microstructure, mechanical properties and corrosion properties of the joints with and without magnetic field were compared and analyzed. [Results] The results showed that pulsed magnetic field significantly improved wetting and spreading behavior of weld, resulting in full-formed joints with larger metallurgical bonding interfaces. Magnetic field did not change main composition of intermetallic compound(IMC) layer, but inhibited diffusion of Fe element and reduced thickness of brittle Fe-Al IMC layer. In addition, electromagnetic stirring made IMC layer wavy and refined grains, thus significantly increasing the interfacial bonding strength by 49.9% compared with that without magnetic field. According to electrochemical measurements, pulsed magnetic field suppressed galvanic corrosion by controlling thickness of IMC layer, and hindered the diffusion and erosion of corrosive medium along grain boundaries by grain refinement. [Conclusion] Pulsed magnetic field can effectively optimize microstructure and morphology of Al/steel CMT welded-brazed joints, enhance interfacial bonding strength and corrosion resistance, which provides a feasible control method for high-quality welding of Al/steel dissimilar materials.更多还原