Preparation And Properties Of Cu-based Composite Material Based On Superplastic Deformation Of Amorphous

In this dissertation, novel Cu/Cu40Zr44Ag8Al8amorphous alloy composite was fabricated through the coextrusion technology, based on the excellent thermoplastic forming characteristics of BMG in the supercooled liquid region (SLR). The thermal stability, structure features and interface behavior of the Cu40Zr44Ag8Al8amorphous alloy and novel Cu/amorphous alloy composite were characterized by OM, DSC, XRD, SEM, TEM and Hv. And the mechanical properties of composite materials was studied by room temperature compression test and three points bending test. Plastic deformation behavior of Cu40Zr44Ag8Al8amorphous alloy in SLR was studied through the high temperature compression test. And high temperature compression test of Cu4oZr44Ag8Al8amorphous alloy were simulated by DEF0RM-3D software.The results of OM, Hv, DSC and XRD indicate that a good surface quality and uniform distribution of core amorphous of composite bar and composite plate were fabricated at extrusion speed of0.007mm/s and extrusion temperature of703K and726K. The SLR of core amorphous decreased3K after coextrusion, the crystallization heat enthalpy also reduced11.58J/g, and corresponding microhardness value slightly increased, but the crystallization of core amorphous does not obviously occur in the process of coextrusion.The results of SEM and TEM indicate that a good interface combination of composite material can obtained by extrusion forming technology, but part of nanocrystalline are formed in the interface locate. The interface width of compound bar in703K preparation is1.64μm, and the interface width of compound plate in703K preparation is2.15μm.Mechanical test results show that the yield strength of composite material is higher than pure copper and lower than as-cast amorphous, but elongation opposite. Yield strength of compound par in703K and726K preparation are475MPa and488MPa, respectively. And the elongation rate of compound par in703K and726K preparation are3.3%and3.04%, respectively.High temperature compression test of as-cast Cu40Zr44Ag8Al8amorphous alloy show that both temperature and strain rate significantly affect the plastic deformation behaviors. Cu40Zr44AggAlg amorphous alloy exhibits Newtonian behavior at high temperature and low strain rates, but becomes non-Newtonian behavior at low temperature and high strain rates. Simulation results fit well with experiment results in Newtonian liquid region, but simulation and experimental results do not match in non-Newtonian liquid region.