The mechanical properties and formation mechanism of Al/Mg composite interface prepared by spark plasma sintering under different sintering pressures

Abstract

In this study, a high strength aluminum-magnesium interface structure was prepared by spark plasma sintering using powder metallurgy. Effects of sintering pressure on the Al–Mg interfacial structure and bonding strength were investigated. The mechanism of formation and evolution of the interface were obtained from characterizing the interface. Results from microstructural observations indicate that interfacial structure changes from solid layers to liquid layers with an increase in sintering pressure; also, bonding strength increases. Maximum interfacial bonding strength reached 59.96 MPa with a sintering pressure of 40 MPa. Each fracture shows characteristics of brittle fracture. Solid layers are composed of a Cu segmentation region and Al3Mg2 and Al12Mg17 intermetallic compound layers. The orientation relationship between Al3Mg2 and Al12Mg17 was determined to be [1‾33]Al3Mg2||[014]Al12Mg17 and 2‾00Al12Mg17||(02‾2)Al3Mg2. Formation of a liquid layer is related to the production of Al–Mg eutectic phase. A model describing the formation and evolution of the Al/Mg interface is proposed.