Fabrication, interfacial characteristics and strengthening mechanisms of ZrB2 microparticles reinforced Cu composites prepared by hot-pressed sintering.

1–9 wt% of ZrB 2 particles are added to Cu to produce ZrB 2 /Cu composites by a hot-pressed sintering process. Microstructures, mechanical and electrical properties of the prepared ZrB 2 /Cu composites are systematically investigated. The results indicated that the relative density and electrical conductivity of the composites decrease with increasing ZrB 2 content. However, the microhardness reaches a maximum value of 100.8 HV 0.2 as ZrB 2 content increases to 7 wt % and then decreases when ZrB 2 content further increases. TEM study reveals that the hexagonal ZrB 2 crystals in size of several micrometers are well embedded in Cu matrix. The interfacial zone consists of both sharp interfaces and amorphous transition layer. Grain refinement strengthening, Orowan strengthening and coefficients of thermal expansion mismatch strengthening contribute to the increment of microhardness and reduce the electrical conductivity. [ABSTRACT FROM AUTHOR]