The trade-off between strength and ductility is a long-standing dilemma in metals and alloys. In this study, we fabricated an ultra-coarse-grained (UCG) Cu-6 wt.%Al alloy with a coarse-grained (CG) surface layer by surface mechanical attrition treatment. Pre-torsional treatment for 45°, 90° and 180° was conducted on the UCG-CG specimens, and the effects of pre-torsional treatment on the microstructures and mechanical properties of the UCG-CG Cu-6 wt.%Al alloy were systematic investigated. It has been shown that the strength and ductility can be simultaneously enhanced via pre-torsional deformation due to the formation of gradient microstructures.

中文翻译：

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通过预扭转处理，将超粗晶粒Cu-Al合金与粗晶粒表面层的强度和延展性很好地结合在一起。

强度和延展性之间的权衡是金属和合金中长期存在的难题。在这项研究中，我们通过表面机械磨损处理制造了具有粗粒（CG）表面层的超粗粒（UCG）Cu-6 wt。％Al合金。对UCG-CG试样进行了45°，90°和180°的扭转前处理，扭转前处理对UCG-CG Cu-6 wt％Al合金的组织和力学性能的影响为系统地调查。已经显示出由于梯度微结构的形成，可以通过扭转前变形同时提高强度和延展性。