Microstructure and properties of Cu-TiNi composites prepared by vacuum hot pressing

Cu-TiNi composites with TiNi volume percentages of 1%, 5%, 10% and 15% were prepared by vacuum hot pressing and hot extrusion. The microstructure, thermal and mechanical properties of the composites were analyzed. The results show that diffusion of elements occurred at the interface between the Cu matrix and the TiNi particles during the preparation process, leading to the formation of a (CuNi)Ti diffusion layer. The TiNi particles are uniformly distributed in the Cu-TiNi composites, with a well-bonded interface with the Cu matrix. Cu matrix has major < 111 > + minor < 001 > fiber textures after hot extrusion. There is a semi-coherent relationship between the Cu matrix and the (CuNi)Ti phase, with an orientation relationship of (111)(Cu)parallel to(103)((CuNi)Ti) and an angle of 18.7 degrees between the two crystal planes. Both the Vickers hardness and the compressive yield strength of the Cu-TiNi composites increased with increasing the volume percentage of the TiNi particles, while the thermal expansion coefficient showed an opposite trend. The thermal expansion coefficient, Vickers hardness and compressive yield strength of the Cu-15% TiNi composite are 14.11 x 10(-6) /K, 154.4 Hv and 460.0 MPa, respectively. (C) 2021 Published by Elsevier B.V.