Microstructure and mechanical properties of Ni/Ti/Al/Cu composite produced by accumulative roll bonding (ARB) at room temperature

Abstract In this work, the Ni/Ti/Al/Cu composite was produced by accumulative roll bonding (ARB) technology at room temperature. The microstructure evolution and mechanical properties of the composite in the ARB process were investigated by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD), micro-hardness and tensile tests. The results showed that a uniform microstructure of the Ni/Ti/Al/Cu composite could be produced by an eight passes ARB process, and no intermetallics were generated at the interfaces. As the ARB pass increased, the thickness of the layers decreased, and the average thickness of Cu layers was 8.5 μm after eight passes. In the ARB process, the average micro-hardness of Ni, Ti, Al, Cu improved from 157.9, 161.3, 23.8, 59.3 HV to 284.3, 254.4, 60.4, 162.2 HV, respectively. Moreover, the micro-hardness was linearly related to the actual equivalent strain. The tensile strength of the composites increased, but the elongation decreased in the ARB process. After eight passes, the tensile strength reached the maximum, which was 298.2 MPa.