Composition of electrical and mechanical functions by controlling of nano-ltructure in Cu-Cr-Ag-Zr system alloys

研究了Cu-0.5mass%Cr合金经形变热处理后的显微组织和力学性能。添加0.15%Zr可提高合金的强度和抗应力松弛性能。强度或抗应力松弛能力的提高是由于Cr沉淀相间距的减小和Cu_5Zr相的析出，或由于Cu_5Zr沉淀相优先在位错上形成而Cr沉淀相不优先在位错上形成。添加0.1%的Ag可提高强度、弯曲成形性和抗应力松弛性。强度或抗应力松弛性的增加归因于Cr沉淀物的间距和时效期间的回复抑制的减少或归因于Ag原子对位错运动的拖曳效应。弯曲成形性的改善可以用后均匀延伸率的增加来解释。研究了等通道转角挤压（ECAP）及后续热处理对Cu-Cr-Zr-Ag合金力学性能的影响。与Cu-CrZr-Ag合金相比，ECAP热处理后合金的0.2%屈服应力、拉伸应力和断裂伸长率均有所提高，但弯曲成形性能和抗应力松弛性能有所降低。

The microstructure and mechanical properties of thermo-mechanically treated Cu-0.5mass%Cr alloys with and without Zr and Ag have been investigated. The addition of 0.15%Zr causes an increase in the strength and the resistance to stress relaxation of the alloy. The increase of strength or stress relaxation resistance is caused by the decrease in inter-precipitate spacing of Cr precipitates and the precipitation of Cu_5Zr phase or by the preferential formation of Cu_5Zr precipitates on dislocations in addition to Cr precipitates on dislocations. The addition of 0.1%Ag improves the strength, the bend formability and the resistance to stress relaxation. The increase in strength or stress relaxation resistance is attributable to the decrease in inter-precipitate, spacing of Cr precipitates and the suppression of recovery during aging or to the Ag-atom-drag effect on dislocation motion. The improvement of bend formability can be explained in terms of the increase in post-uniform elongation. The effect of equal-channel angular pressing (ECAP) and subsequent heat treatment on the mechanical properties of the Cu-Cr-Zr-Ag alloy has also been studied. The heat-treated ECAP alloy shows larger values of 0.2% proof stress, tensile stress and elongation to failure, but lower bend formability and stress relaxation resistance than the thermo-mechanically treated Cu-CrZr-Ag alloy.