Study on the interfacial microstructure and fracture mechanism of Al/Mg composites with Zn interlayer by cyclic hot pressing

Abstract

Using the cyclic hot pressing method, Al/Mg laminated composites with a Zn interlayer were prepared, and the effect of temperature on the composite interfaces was studied. At 420℃, the composites interface is composed of HCP-Zn solid solution near the Al side and Laves phase near the Mg side. At 460℃, FCC-Al phase and τ-phase appear near the Al side, while τ-phase and HCP-Mg solid solution appear near the Mg side. Above 500℃, the interface is mainly composed of Al-Mg intermetallic compounds. The change of solubility during the formation of the composite causes the polarization of solute atoms in Zn and Al solid solutions, resulting in defects, such as increased grain boundary stress and lattice distortion. These defects lead to failure of the interface near the aluminum side of the composites. Composites prepared at 420℃ show the best ductile fracture properties. With the increase of preparation temperature, the fracture mode is transformed into brittle fracture induced by β-phase.