【摘要】 针对铜/钢异种金属连接时由热膨胀系数不匹配引起的裂纹问题，使用2种AgCuZnSn药芯钎料，并通过高频感应钎焊方式连接Cu/Q235A异质金属。研究了2种药芯钎料对接头微观组织、应变分布及断裂行为的影响。结果表明：2种钎料在Cu侧具有良好的界面反应，而在Fe侧出现了孔洞缺陷。与采用BAg30T钎料的接头相比，采用BAg25TS钎料的接头具有较弱的织构特征、较低的局部取向差(KAM)值以及较少的变形晶粒分布，因此钎缝中的残余应力更小，接头最大抗拉强度与抗剪强度分别达到了206 MPa与116 MPa。接头为沿晶断裂与穿晶断裂的混合断裂模式，裂纹萌生于钎缝中高残余应力区域，随后裂纹沿着Cu基固溶体相及Ag基固溶体相界面进行扩展。更多还原

【Abstract】 For the crack issues caused by mismatched thermal expansion coefficients in copper/steel dissimilar metal joints, two types of AgCuZnSn flux-cored filler metals were used to join Cu and Q235A dissimilar metals via high-frequency induction brazing. The effects of two types of flux-cored filler metals on the microstructure,strain distribution, and fracture behavior of the joint were investigated. The results indicate that both filler metals exhibit good interfacial reactions on the Cu side, while porosity defects are observed on the Fe side.Compared with joints using BAg30T filler metal, the joints employing BAg25TS filler metal exhibit weaker textural characteristics, lower kernel average misorientation(KAM) values, and a smaller distribution of deformed grains. Consequently, residual stresses in the weld zone are lower, and the maximum tensile and shear strengths of the joints reach 206 MPa and 116 MPa, respectively. Fracture analysis of the joint indicates a mixed fracture mode involving both intergranular and transgranular fracture. The crack originated in a region of high residual stress within the brazing joint and subsequently propagated along the interface between the Cubased solid solution phase and the Ag-based solid solution phase.更多还原