Microstructural characterization of the Mg/Cu/Al diffusion bonded joint

A vacuum hot-pressed diffusion bonding method was used to prepare an Mg/Cu/Al laminated composite. Both the Mg/Cu and Al/Cu interfaces were investigated by means of scanning electron microscopy, electron probe microanalysis, X-ray diffraction spectrometer system and Vickers microhardness test. The results showed that two kinds of intermetallic compounds, Al ₄Cu₉ adjacent to the Cu side and Al₂Cu adjacent to the Al side, were formed in the interface of Al-Cu. Meanwhile, Mg ₂Cu was formed at the interface of Mg/Cu. The maximum value of shear strength is 13.1 MPa and the fracture of the joints had taken place at the Mg-Cu interface. The microhardness of the interface increased due to the formation of the intermetallic compounds, which is the main cause leading to poor bond properties.