双相层状复合Cu-24%Ag合金的组织与性能

Evolution of Microstructure and Properties of Two-phase Cu-24%Ag Multilayered Composite

采用冷轧和时效工艺制备了Cu-24%Ag(质量分数)合金板材,研究了轧制过程中合金组织与性能的演变规律,讨论了合金强化和电导率与组织变化的关系。剧烈的轧制变形后,合金组织演变成Cu基体和Ag相交替排列的纳米层状结构,Cu基体中包含大量细小的Ag析出相纤维,一些Ag层区域分布着(Cu+Ag)共晶体。当变形至94%左右时,纵截面组织出现剪切带。随变形量增大,Cu基体和Ag层之间的相界面间距、Ag析出相纤维间距和共晶体片层间距均逐渐减小至几十纳米,强化效应显著增强,使合金的硬度在变形量大于96%时急剧增大。建立了Cu/Ag界面引起的电阻率增幅与变形量的关系,可以反映轧制变形引起的组织细化对合金电导率的影响规律。

Cu-24wt%Ag alloy sheets were prepared by cold rolling and aging and the evolution of microstructures,mechanical properties and electrical conductivity was investigated. The relationship of the strengthening and conductivity with microstructure refinement of the alloy was discussed. Results show that after severe cold rolling,the microstructure develops into nano-layered structure of Cu and Ag arranged alternatively,with numerous Ag nano-fibers embedded in Cu matrix and（Cu＋Ag） eutectics distributed in Ag areas. Shear bands occur in longitudinal sections as the strain reaches 94% or so. With increasing the rolling strain,spacing of Cu/Ag interface,Ag fibers and eutectic lamellae decreases gradually to nanoscale,significantly enhancing the strengthening effect,and hence the hardness increases rapidly when the strain exceeds 96%. The relationship between the resistivity increment caused by Cu/Ag interface and rolling reduction was established,reflecting the influence rule of microstructure refinement on electrical conductivity in the rolling process.