Research on multi functional Cu-Cr-Zr alloys in mechanical and electrical properties produced by controlling its nano-structure

本研究通过控制铜合金的纳米结构，制备出导电性能和力学性能俱佳的铜合金。采用等径角挤压法制备了不同合金元素浓度的超细晶Cu-Cr和Cu-Cr- zr稀合金，并对其进行热处理。(1) ECAP后时效使析出硬化的超细晶粒组织在热、力学两方面都较为稳定。(2)找到了最佳时效条件，以保证最佳的高周疲劳性能，同时具有良好的导电性、强度和延展性。(3)与经冷加工和热处理制备的普通Cu-Cr-Zr合金相比，拉伸性能和HFC性能有显著改善，延展性也有改善。针对不同结构的UFO结构，采用不同应变路径的多个ECAP制备超细晶粒Cu-0.36Cr合金。(1)ECAP已经能够生产具有相当大的均匀变形量的高强度UFG材料。(2) ECAP材料的拉伸强度和高周疲劳性能受应变路径、晶粒形状和晶体织构的影响较小。研究了ECAP法制备的超细晶Cu-Cr-Zr合金的抗断裂和抗疲劳性能。(1)疲劳裂纹扩展行为与试样取向无关，证明ECAP形成了均匀的结构，具有相当的各向同性。

This research has been conducted to produce the excellent Cu alloy in combination with good electrical conductivity and mechanical properties by controlling its nano-structure.1.The ultrafine grain (UFG) Cu-Cr and Cu-Cr-Zr dilute alloys with different concentrations of alloying elements have been fabricated by ECAP (Equal Channel Angular Pressing), and followed by heat treatment.(1)The post ECAP aging makes the precipitation hardened ultrafine grain structure rather stable under both thermal and mechanical influence.(2)Optimal aging conditions are found to ensure the best high cycle fatigue performance in combination with good electric conductivity, strength and ductility.(3)The significant improvement of tensile and HFC properties observed together with improvement in ductility if compared to ordinal Cu-Cr-Zr alloys fabricated by cold working and heat treatment.2.The ultra fine grain Cu-0.36Cr alloy was fabricated by multiple ECAP with different strain path, aiming at fabrication of UFO structures with different structures.(1)ECAP has been capable of producing high strength UFG materials having a considerable amount of uniform deformation.(2)The tensile strength and high cycle fatigue properties are just slightly affected by the strain path, grain shape and crystallographic texture of ECAP specimens.3.The fracture and fatigue resistance of ultrafine grain Cu-Cr-Zr alloy produced by ECAP was investigated.(1)The fatigue crack growth behavior is independent of the specimen orientation, proving the ECAP create a uniform structure with rather isotropic properties.