Effects of interface characteristics of Cu/Cr phases on the contact performance of Cu-25Cr alloy contact material

The microstructure and interface of Cu/Cr phases in vacuum casting Cu-25Cr alloy and sintered CuCr25 p/m contact materials were investigated by transmission electron microscopy (TEM). Some fine secondary Cr-dendrites have preferred orientation relationships of (110)_Cr // (111)_Cu and [011]_Cr // [1macr12]_Cu, and a single set of misfit dislocations separated by a space of ~6 nm are distributed on the semicoherent interfaces of Cr/Cu phases, which shown that the interface structure of two phases in the Cu-25Cr alloy material is better coordination. In contrast to the Cu-25Cr alloy material, incoherent interface between Cr/Cu particles in CuCr25 p/m material were formed by frictional force, and a few inclusions of Al₂O₃ and Cr₂O₃ were aggregated on the lose bonding interface of Cr/Cu particles in the materials. Thereby the effects of interface structure of Cr/Cu phases in the CuCr contact materials on the mechanical properties, fracture characteristics and contact performance of contact materials are discussed.