Ultrafine grain of pure copper 99.98% was produced by severe plastic deformation using the equal-channel angular pressing (ECAP) method. Copper samples were ECAPed from 1 to 8 passes following route BC; fine grain sizes of 250 nm were developed after eight passes. Important enhancement in the mechanical strength properties was obtained. Subsequent heat treatments (HT) were carried out to evaluate the thermal stability of the grains of the ECAPed samples. Microstructure and mechanical properties were evaluated to determine the recovery and recrystallization temperatures. Differential scanning calorimetry (DSC) tests were conducted to all samples in order to determinate these temperatures. The activation energy of the recrystallization process was also determined by the DSC technique and good correlation was obtained with the microstructure and mechanical properties. An important decrease in the mechanical properties and an increasing heterogeneous grain size distribution were observed when heat treatments were performed.
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机译：使用等通道角挤压（ECAP）方法通过剧烈的塑性变形可以生产出99.98％的纯铜超细晶粒。沿着B C 路线从1到8遍ECAP铜样品；经过八次加工后，形成了250 nm的细晶粒。获得了机械强度性能的重要提高。随后进行热处理（HT），以评估ECAPed样品晶粒的热稳定性。对微结构和机械性能进行了评估，以确定恢复温度和重结晶温度。对所有样品进行差示扫描量热法（DSC）测试，以确定这些温度。还通过DSC技术确定了重结晶过程的活化能，并获得了与显微组织和力学性能的良好相关性。当进行热处理时，观察到机械性能的显着降低和不均匀晶粒尺寸分布的增加。
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