Interfacial bonding mechanism and mechanical properties of adding CuZn alloy fibre for Cu/Al composite

Abstract

The heterogeneous interface constituted by Cu and Al were diffusion-bonded with CuZn alloy fibre interlayer under different bonding parameters, which was compared with directly bonded Cu/Al interface to analyze the effects of the different intermetallic compounds (IMCs) occurred at the joining interface on the interface mechanical properties. The interface microstructure was analyzed by scanning electron microscope (SEM), the compositions profiles across the joining interface were measured by energy dispersive spectroscopy (EDS), the phase and grain in the bonding interface of a Cu/Al bond were carefully investigated via electron backscatter diffraction technique (EBSD), the results show that the interface phase of Cu/Al composites grows irregularly, which leads to the low uniformity of interface properties. By adding CuZn alloy fibre, the interface of Cu/Al shows cellular skeleton and promotes the uniform diffusion of interface. When the bonding time was 570 °C for 60 min, the average shear strength of Cu/CuZn/Al interface reached 60.7 MPa. Compared with Cu/Al interface, the standard deviation of shear strength decreased from 18.7 to 1.6, and the variance decreased from 3.7 to 1.1. • The diffusion of Cu and Al was promoted by the introduction of Zn. • CuZn alloy can improve the interface homogeneity of large area Cu/Al composites. • When CuZn alloy fibre was added, the fracture mode changed to mixed fracture. • The bonding time has a great effect on the uniformity of the interface.