Preparation and properties of TiB2 particles reinforced Cu-Cr matrix composite

Cu-0.5Cr-1.5TiB2 composites prepared by different melting processes were investigated in the present study. The optimum reaction temperature for the dispersed distribution of TiB2 particles is 1300 °C and a higher temperature is not appropriate due to the high loss of solute elements. Holding time should be 10 min to make TiB2 particles exhibit a relatively homogeneous distribution in the matrix. An argon shield is necessary to ensure obtaining the desired chemistry. The typical TiB2 particles with equiaxed and symmetric morphology are observed in the matrix, while particles with irregular morphology are obtained when the growth process is inhibited by adjacent particles. After aging, the better mechanical properties are obtained by composite prepared at the optimum melting process. Strengthening is comprised of a dislocation pile-up mechanism of TiB2 particles, precipitation strengthening of Cr particles and strain strengthening. TiB2 particles slightly decrease the electrical conductivity, which indicates a minor contribution from interface scattering. The conductivity exhibits an obvious increase after aging because of the sharp decline of impurity scattering.