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采用XRD、EBSD和TEM技术对单晶高纯Cu(99.999%)经等通道转角挤压(ECAP)A路径过程中的形变织构进行了研究,测试了ECAP后单晶Cu的力学性能和导电性能,并分析了变形过程中织构演变机理及其对力学性能和导电性能的影响。结果表明:原始单晶Cu经2道次变形后,晶内出现了微小的等轴状形变结构;4道次变形后,形成了(110)取向一致的形变带结构;8道次变形后,单晶组织开始破碎,晶粒取向又逐渐趋于(111)面,形成了{111}<110>和{111}<112>织构及较弱的{001}<100>再结晶织构。中、低应变下,形成稳定取向的{hkl}<110>织构,可有效降低晶界对电子的散射作用,使电导率略有增加,同时有利于大幅度提高材料的加工硬化率。单晶Cu变形初始阶段形成了大量小角度晶界,随着应变的增加,小角度晶界逐渐向大角度晶界转变。由于变形过程中位错积聚及晶界密度增加对位错运动起到阻碍作用,3道次变形后,抗拉强度从168 MPa增加至400 MPa,延伸率从63%减小至27.3%,在随后的变形中抗拉强度增加缓慢,延伸率略有回升。前8道次变形中硬度不断增加,8道次变形后出现了再结晶,导致随后的挤压过程中硬度不稳定。
The deformation texture of single-crystal high-purity Cu (99.999%) through ECAP path A was investigated by XRD, EBSD and TEM techniques. The mechanical properties and conductivity The mechanism of texture evolution and its effect on mechanical properties and electrical conductivity during the deformation process were analyzed. The results show that there are tiny equiaxed deformable microstructures in the original single-crystal Cu after two passes of deformation. After four passes deformation, (110) The structure of {111} <110> and {111} <112> texture and the weak {001} <100> recrystallization texture are formed. Under the medium and low strain, the {hkl} <110> texture with stable orientation is formed, which can effectively reduce the scattering effect of the grain boundary on the electrons and increase the conductivity slightly, and at the same time it is beneficial to greatly improve the work hardening rate of the material. A large number of small-angle grain boundaries were formed during the initial stage of single-crystal Cu deformation. With the increase of strain, the small-angle grain boundaries gradually transformed into large-angle grain boundaries. Due to the dislocation accumulation and the increase of the grain boundary density during the deformation process, the dislocation movement hindered the displacement. After three passes deformation, the tensile strength increased from 168 MPa to 400 MPa and the elongation decreased from 63% to 27.3% Subsequent deformation increases slowly and the elongation slightly increases. The hardness of the first eight passes increased continuously, and after eight passes, recrystallization occurred, which led to the instability of hardness in the subsequent extrusion.