镀钴对铝/钢电磁脉冲焊接头性能的影响

Effect of Cobalt Plating on Performance of Al/Steel Magnetic Pulse Welded Joints

在Q235钢板待焊面的表面电镀一层钴金属薄膜,再采用电磁脉冲焊接(MPW)技术对1060铝板/Q235钢板进行焊接,运用扫描电子显微镜(SEM)观察、能谱分析(EDS)、显微硬度测试及拉伸性能分析等手段对其焊接接头界面形貌、微观组织及力学性能进行了研究,并与Al/无镀层钢接头进行了对比。结果表明,铝/无镀层钢电磁脉冲焊接焊缝由中间未焊接区及两侧连接区组成,具有直缝、小波及大波形界面形貌,波形界面的过渡区宽度约为6μm,过渡区存在FeAl_(3)脆性金属间化合物,拉剪强度为122.22 MPa。镀钴钢/铝焊接界面的材料成形良好,形成明显的大波形连接界面,过渡区宽度约为8μm,镀层钴元素有效阻碍了铁元素向过渡区扩散,避免了铝铁金属间化合物的生成,增大了波形界面,有效提高了接头的力学性能,拉剪强度为137.78 MPa,提高了12.7%。

Cobalt metal film was plated on the surface of Q235 steel plate to be welded,and then the welding of 1060 aluminum plate/Q235 steel plate was carried out by using magnetic pulse welding(MPW)technology.Through the scanning electron microscopy(SEM)observation,energy spectrum analysis(EDS),microhardness testing and tensile properties analysis,the interface morphology,microstructure and mechanical properties of the welded joint were studied,and it was compared with the Al/non coated steel welded joint.The results show that the aluminum/non coated steel EMP weld is composed of the middle unwelded zone and the connection zone on both sides,and the interface has straight weld,small waveform and big waveform.The transition zone width of the waveform interface is about 6μm,and the brittle intermetallic compound FeAl_(3) exists in the transition zone,and the tensile-shear strength is 122.22 MPa.The Co-plated steel/aluminum welding interface is well formed,and obvious big waveform interface is formed,and the width of the transition zone is about 8μm.The Co element of the plating layer effectively hinders the diffusion of the Fe element into the transition zone,and it avoids the generation of aluminum-iron intermetallic compounds,increases the waveform interface,effectively improves the mechanical properties of the joint.The tensile-shear strength is 137.78 MPa,which increases by 12.7%.