Microstructure and interface evolution of diamond/Cu composites prepared via ultrasonic additive manufacturing (UAM)

Diamond-copper laminated composites with Cr-coating were prepared by ultrasonic additive manufacturing method. The microstructure and interfacial configuration between Cr-diamond and copper matrix were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), focused ion beam (FIB), and high-resolution transmission electron microscopy (HRTEM). Additionally, the microstructure evolution of the matrix around Cr-diamond particles were evaluated using electron backscatter diffraction (EBSD) method. The results reveal that the Cr-diamond achieves excellent solid bonding with the matrix due to violent plastic deformation. Moreover, we observe significant grain refinement and dynamic recrystallization at the interface of the matrix. The thermal conductivity of Dia/Cu composites is 428.07 ± 3.3W/mK and the diamond volume fraction is 8.8%.The study of this process can open up new avenues for low-temperature, low-pressure, free-design, and open fabrication of particle-reinforced metal matrix composites.