热压焊接制备的Cu / Al双金属的界面组织和剪切强度

Interfacial microstructure and shear strength of a Cu/Al bimetal fabricated by hot press welding

摘要:

采用扩散焊（DFW）技术制备了Cu/Al双金属，连接温度范围683-803K，连接时间范围20-80min，连接压力15MPa。Cu/Al双金属界面处的SEM试验结果表明，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80min，Cu/Al界面处形成了Al4Cu9，Al3Cu4，AlCu、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723 K的焊接温度下进行20分钟焊接后，Cu / Al双金属的剪切强度最高为63.8 MPa。

关键词:铜铝双金属;界面微观结构;金属间化合物;剪切强度

Abstract:

Cu/Al bimetals were fabricated by diffusion welding (DFW) at welding temperatures ranging between 683 and 803 K, welding time between 20 and 80 min, and a welding pressure of 15 MPa. The scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) results of the Cu/Al interface showed that the width of interface layer gradually increased with increasing welding temperature and prolonged welding time. Following welding at 803 K for 80 min, intermetallic compounds (IMCs) of Al4Cu9, Al3Cu4, AlCu, and Al2Cu occurred at the Cu/Al interface from the copper side to the aluminum side. The IMCs occurred in the sequence of Al2Cu, AlCu, Al3Cu4, and Al4Cu9 . Shear test of Cu/Al bimetal showed brittle facture, and the interfacial strength increased with lower amount of IMCs. A maximum shear strength of the Cu/Al bimetal of 63.8 MPa was obtained following DFW at a welding temperature of 723 K for 20 min.

Key words:Cu/Al bimetal; Interfacial microstructure; Intermetallic compounds ; Shear strength