单晶铜ECAP/Bc路径形变结构与力学性能

Deformation Structure and Mechanical Properties of Single Crystal Copper Deformed by Route ECAP/Bc

采用电子背散射衍射技术(EBSD)、XRD,研究了单晶铜在等通道转角挤压(ECAP)/Bc路径4道次变形过程中的形变结构演变,并检测了变形材料的力学性能。结果表明:低道次变形不改变单晶铜的宏观取向;2道次变形后,材料微观组织中出现取向一致的剪切带,与ED轴成15°～20°角,晶粒内部出现了形变织构{111}<112>;经过4道次变形后,剪切带与ED轴夹角不变,但倾斜方向与2道次相反,形变织构不发生改变,且未出现大角度晶界;5道次变形后,抗拉强度由168 MPa提高至395 MPa,延伸率则从63%降至26.5%,硬度由600 MPa提高到1250 MPa,之后趋于平缓;由于位错堆积,材料塑性变差,断口颈缩面积变大。ECAP可使单晶铜在晶粒未破碎的情况下得到强化。

The deformation structure of single crystal copper during 4 passes equal channel angular pressing（ECAP） through route Bc was investigated by electron backscatter diffraction（EBSD） and XRD, and the mechanical properties of the deformed material were measured. The results show that the macroscopic orientation of the single crystal under low pass deformation does not change. After 2 passes, an orientation-ordered shear band appears and inclines within the range of 15°-20° in the ED direction, with a deformed texture {111}112 on the grains; After 4 passes, the angle between the shear band and the ED direction is constant, while the inclined direction is opposite to that of the 2 passes, the texture of the material is still {111}112 texture, and no large angle grain boundary is present; After 5 passes, the tensile strength increases from 168 MPa to 395 MPa, and the elongation decreases from 63% to 26.5%, the material hardness increases from 600 MPa to 1250 MPa, and then tends to change little. Because of the accumulation of dislocations, the plastic deformation ability of the material becomes deteriorated, and the necking area increases. ECAP has a positive effect on increasing the strength of single crystal copper with unbroken grains.