大变形Ag-10Cu原位纤维复合材料的应变强化效应

Strain Strengthening of Ag-10Cu in situ Filamentary Composite Prepared by Heavy Deformation

摘要:

利用热挤压加冷拉拔制备Ag-10Cu原位纤维复合材料。Ag-10Cu合金铸态及挤压态结构由Ag基体、(Ag+Cu)共晶体和Cu沉淀组成。经大变形后变成Ag基体加Cu纤维的两相组织，合金中的Cu相转变成Cu纤维，其尺寸d随拉拔应变η呈幂指数关系变化，且可拟合为d=d0exp(－0.144η)，其中d0是与Cu沉淀初始尺寸有关的系数。讨论了材料强度的两个阶段变化及其强化机制。所制备的材料可以达到抗拉强度接近1 GPa及电导率大于60% IACS的较优性能组合。还讨论了中间热处理的影响

Abstract:

Ag-10Cu in situ filamentary composite was prepared by hot extrusion and cold wire drawing. The as-cast and as-extruded Ag-10Cu alloys consist of Ag matrix, (Ag+Cu) eutectic and Cu precipitates which will become a structure of Ag matrix and Cu filaments after heavy deformation. The size of Cu filaments, transformed from coarse Cu precipitates, changes with drawing strain, and their relationship can be expressed as d=doexp(–0.144η). Two-stage strengthening characteristics were obtained and the strengthening mechanism of this composite was discussed. A combination of ultimate tensile strength approaching 1 GPa and electrical conductivity exceeding 60% IACS can be achieved for this composite. The effect of intermediate heat treatment was also discussed