Interface characterization and mechanical properties of BMG/Cu composites prepared by coextrusion

A BMG/Cu composite rod and a plate with a Cu40Zr44Ag8Al8 BMG core and a pure copper sleeve have been fabricated by the coextrusion process. The interfaces between the two materials have been analyzed through various techniques including optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). Good interface adhesion with metallurgical bonding has been formed, corresponding to two diffusion layers of about 100 nm near the Cu and BMG parts. An interface bonding model has been constructed based on these observations. The fracture mode of the BMG/Cu composite has been also characterized by compression tests, which involves debonding at the interface and plastic deformation of the Cu sleeve.