扩散连接制备Cu/Al双金属及其界面组织与剪切强度

Interfacial Microstructure and Shear Strength of Cu/Al Bimetal Fabricated by Diffusion Welding

采用扩散焊(DFW)技术制备了Cu/Al双金属,连接温度范围683~803 K,连接时间范围20~80 min,连接压力15 MPa。Cu/Al双金属界面处的SEM实验结果表明,随着焊接温度的升高和保温时间的延长,界面层厚度逐渐增加,在连接温度为803K,连接时间80 min时,Cu/Al界面处形成了Al4Cu9,Al3Cu4,AlCu和Al2Cu金属间化合物(从铜侧到铝侧)。根据扩散动力学,金属间化合物(IMCS)的生成顺序为Al2Cu、Al4Cu9、AlCu、Al3Cu4。Cu/Al双金属的剪切试验显示为脆性断裂,并且界面强度随着IMC的减少而增加。在723K的焊接温度下进行20min焊接后,Cu/Al双金属的抗剪切强度最高为63.8 MPa。

Cu/Al bimetals were fabricated by diffusion welding(DFW)at welding temperatures of 683~803 K for a welding time of 20~80 min under the welding pressure of 15 MPa.The scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)results of the Cu/Al interface show that the width of interface layer gradually increases with increasing the welding temperature and prolonging the welding time.After welding at 803 K for 80 min,intermetallic compounds(IMCs)of Al4Cu9,Al3Cu4,AlCu,and Al2Cu form at the Cu/Al interface from the copper side to the aluminum side.The IMCs appear in the sequence of Al2Cu,Al4Cu9,AlCu,and Al3Cu4.Shear test of Cu/Al bimetal shows brittle facture,and the interfacial strength increases with lower amounts of IMCs.The maximum shear strength of 63.8 MPa for the Cu/Al bimetal is obtained after DFW at a welding temperature of 723 K for 20 min.