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Microstructure and properties of TiB2 particles reinforced Cu–Cr matrix composite

Zhang, Pengchao, Jie, Jinchuan, Li, Hang, Wang, Tongmin, Li, Tingju
Journal of materials science 2015 v.50 no.9 pp. 3320-3328
alloys, boron, chromium, copper, electrical properties, hardness, melting, microstructure, temperature, titanium
Copper–chromium matrix composites reinforced by TiB₂particles were prepared by in situ reaction between titanium and copper–boron alloy in the melt. The microstructures, mechanical, and electrical properties of the composite were investigated under as-cast and aging conditions. The results indicate that the TiB₂particles are formed by in situ reaction in matrix. The addition of TiB₂in composite reduces the segregation degree of Cr particles in matrix and inhibits the coarsening of Cr particles at high aging temperature. High hardness of Cu–Cr–TiB₂composite is achieved due to the multiple hardening mechanisms, which are in situ TiB₂particles hardening and precipitation hardening from Cr particles. The wear resistance of composite presents a dramatic improvement due to the formation of TiB₂particles, and TiB₂particles have significant effect on wear mechanism of Cu–Cr–TiB₂composite. The conductivity of composite is lower than that of Cu–Cr alloy, which is attributed to higher resistivity of TiB₂particles and the incremental interface scattering caused by TiB₂particles. But the composites with high TiB₂content still have considerable conductivity after aging.