Cu和Ni中间层对铝/钢异种金属搅拌摩擦搭接焊接头界面微观组织及剪切性能的影响

Effect of Cu and Ni interlayers on interfacial microstructure and shear properties of aluminum/steel dissimilar metal friction stir lap welded joints

采用搅拌摩擦搭接焊(FSLW)对添加Cu和Ni中间层的6061-T6铝合金和QP1180钢进行焊接,研究接头微观组织及力学性能。结果表明, FSLW可以成功制备出成形性良好的Al-Cu-Fe及Al-Ni-Fe接头, Cu粉和Ni粉均与基体结合良好。Cu粉阻隔了Al-Fe之间的元素扩散,接头金属间化合物(IMCs)种类为Al Cu和Al_(3)Cu_(2),无Al-Fe IMCs生成;Ni粉无法完全阻隔Al-Fe之间的反应, IMCs种类为Al_(3)Ni_(2)和Al Fe_(3)。Al-Ni-Fe接头中产生的IMCs与基体之间的平均错配度低于Al-Cu-Fe接头中IMCs与基之间的平均错配度,表明Al-Ni-Fe接头中产生的IMCs与基体之间的结合强度优于Al-Cu-Fe接头中产生的IMCs与基体之间的结合强度,因此Al-Ni-Fe接头剪切强度(7.86 k N)优于Al-Cu-Fe接头剪切强度(4.62 k N)。

The 6061-T6 aluminum alloy and QP1180 steel with Cu and Ni interlayers were welded by friction stir lap welding(FSLW)to study the microstructure of the joints and the mechanical properties were studied.The results show that Al-Cu-Fe and Al-Ni-Fe joints with good formability are successfully prepared by FSLW,and both Cu and Ni powders are well combined with the matrix.The Cu powder inhibits the element diffusion between Al-Fe,the intermetallic compounds(IMCs)in the joints are AlCu and Al_(3)Cu_(2),and no Al-Fe IMCs are generated.Ni powder can not entirely inhibit the reaction between Al-Fe,resulting in the presence of Al_(3)Ni_(2) and AlFe_(3) IMCs in the joint.The average lattice mismatch of IMCs and matrix in Al-Ni-Fe joint is lower than that in Al-Cu-Fe joint,indicating that the bonding strength between IMCs and matrix in Al-Ni-Fe joint is better than that in Al-Cu-Fe joint.Therefore,the shear strength of Al-Ni-Fe joint(7.86 kN)is better than that of Al-Cu-Fe joint(4.62 kN).