中文摘要：

采用多轴反复挤压法得到了不同挤压道次下的Cu-0．7Cr合金的微观组织，研究了挤压道次对合金时效析出行为和性能的影响。结果表明，多轴反复挤压可细化合金晶粒，提高孪晶含量，并增加位错密度。时效处理时，缺陷将促进纳米cr颗粒析出，显著提高合金的硬度和电导率。挤压5道次后，Cu-0．7Cr合金经时效后可获得理想的硬度和电导率组合，硬度和电导率与未挤压的固溶时效试样相比，分别提高了160％和20％。

英文摘要：

Cu-0.7Cr alloys were prepared and subjected to multiaxial accumulative pressing （MAP）. Dif- ferent initial microstructure was achieved at different pressing passes to investigate comparatively the effects of pressing passes （pressed microstructures） on the aging behaviors and mechanical/electrical properties of the Cu-0.7Cr alloy. The results reveal that MAP is effective in refining the grains, increas- ing twin content, and raising dislocation densities. In the following aging treatment, these defects can promote the precipitation of nanosized Cr particles and hence improve hardness and simultaneously en- hance electrical conductivity of the Cu-0.7Cr alloys. Under five pressing passes, the Cu-0.7Cr alloys ex- hibit the desirable comprehensive behavior of hardness and electrical conductivity, which is increased by 160% and by 20%, respectively , compared with ones without MAP.