Cu-25Cr合金触头材料中Cu/Cr相界面的特性

用透射电子显微镜(TEM)的选区电子衍射、衍衬及X射线能谱分析了真空熔铸Cu-25Cr合金触头材料和烧结CuCr25粉末合金触头材料中Cu/Cr两相界面及其显微组织。一些细小的Cr二次枝晶与Cu基体有择优取向关系,即(110)Cr∥(111)Cu和[011]Cr∥[112]Cu,间距约6nm的单列错配位错分布在Cr/Cu两相的半共格界面上,这表明Cu-25Cr合金材料中Cr/Cu两相的界面具有更好的协调性。与Cu-25Cr合金材料相反,CuCr25粉末合金烧结材料中Cu/Cr粒子之间形成的是非共格界面,且有少量的Al2O3和Cr2O3等夹杂物聚集在松散的Cu/Cr颗粒间的界面上。据此,本文讨论了CuCr触头材料中Cu/Cr两相间的界面结构对材料机械性能、断裂特性及电接触性能的影响。

Interface Characteristics of Cu/Cr Phases in 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//[112]Cu, and a single set of misfit dislocations separatedby 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 interfacebetween 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 Cu/Crparticles 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.