Cu-Ag合金中析出相界面结构及其对合金性能的影响

Interface structure between Ag precipitates and Cu matrix and its effect on the properties of the Cu-Ag alloy

采用真空感应熔炼法制备Cu-6%Ag和Cu-24%Ag,并进行退火和时效处理,观察了合金中析出相与基体的位向关系及界面结构,分析了析出相对合金强化和导电特性的影响.析出相与Cu基体之间具有(100)Cu∥(100)Ag及〈110〉Cu∥〈110〉Ag位向关系,存在半共格界面,在(111)面上平均每隔9个晶面间距出现一个刃型位错以协调点阵错配.析出相与Cu基体这种特定的位向关系及界面结构能有效地阻碍基体中位错的运动,在产生析出相强化作用的同时几乎不影响合金的电传导行为.随Cu-6%Ag时效时间的延长,析出相数量增多,合金硬度显著上升而电阻率持续下降.时效过程中析出相数量、形态及界面结构是导致合金力学和电学性能变化的主要原因.

The Cu-6% Ag and Cu-24% Ag were cast and annealed or aging treated to precipitate Ag secondary particles from supersaturated Cu matrix. The interface and orientation relationship between Ag precipitates and Cu matrix were investigated. The effect of Ag precipitates on the mechanical and electrical properties of the alloys was discussed. There are a strict orientation relationship, （100）Cu// （100）Ag and （ll0）cu// （110） Ag, and semi-coherence interface between Ag precipitates and Cu matrix. One dislocation exists in average nine （111）cu lattice intervals to adjust the lattice misfit at the interface. The strict orientation relationship and semi-coherence interface may produce significant strengthening affect and hardly increase the electron scattering in the alloys. With prolonging aging time the amount of Ag precipitates and the hardness of the alloys increase but the electrical resistivity decreases. The changes of the amount, morphology and interface structure of the precipitates should be responsible for the change of the properties during aging treatment.