应变程度对Cu-12%Ag合金纤维相形成及导电性能的影响

EFFECTS OF DRAWING STRAIN ON FORMATION OF FILAMENTARY STRUCTURE AND CONDUCTIVITY FOR Cu-12%Ag ALLOY

通过冷拉拔制备了纤维相增强的Cu-12％Ag合金(质量分数),研究了纤维组织形成过程及变形程度对合金电导率的 影响,讨论了影响电导率的机制并建立了分析模型.随着变形程度的增加,共晶体演变成细密的纤维柬结构,电导率降低.合金导 电主要依赖于Cu基体而非共晶体,共晶纤维束与Cu基体界面间距随应变率增大而减小是合金导电性能下降的主要因素.根据 界面散射模型建立了电阻率与变形程度之间的函数关系,可预测不同应变条件下合金的导电性能.

Cu-12%Ag (mass fraction) filamentary composite was prepared by heavy cold drawing. The evolution of filamentary microstructure and the effect of strain level on the electrical conductivity of the composite were investigated. The mechanism responsible for the electrical conductive behavior was discussed. With increasing draw ratio, the original eutectic colonies develop into fine fibrous bundles and the electrical conductivity decreases. Electrical conduction of the composite depends mainly on the Cu matrix instead of eutectic fibrous bundles. The conductive loss with strain enhancement can mainly be attributed to the reduction of interfacial spacing between the Cu matrix and eutectic fibrous bundle. The quantitative relationship between the electrical resistivity and draw ratio was derived on the basis of a size-effect model and can be utilized to predict the electrical conductive level of the composite under different strain conditions.