We subjected an aged Cu-24wt%Ag ingot to cold drawing to create a high-strength nanostructured composite wire with both Cu-rich proeutectic and Ag-rich eutectic components. During the drawing, a fine lamellar structure (average spacing 20 ± 6 nm) developed in the proeutectic component, which contained a high density of Ag fibers (average width below 5 nm) embedded in the matrix. In the eutectic component, a relatively coarse structure developed, with an average Ag grain size around 100 nm. The result of such a bimodal size of Ag fibers was ultra-high bending plasticity, i.e., the drawn wire tolerated 59% bending strain at the outermost edge, 15 times its tensile elongation (3.6%). During our bending test, dynamic recovery and partial recrystallization occurred more near the inner edge than near the outer edge and primarily in the eutectic component. High bending strain caused some of the thicker Ag fibers to become discontinuous and lose their original alignment. This structural evolution increased local plasticity, resulting in an unexpectedly high achievable bending strain, which is unusual in nano-sized, Ag-fiber-reinforced high-strength composites.

中文翻译：

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高强度纳米复合材料中的超高局部塑性

我们对老化的 Cu-24wt%Ag 锭进行冷拔，以创建具有富铜先共晶和富银共晶成分的高强度纳米结构复合线。在拉伸过程中，在共晶组分中形成了精细的层状结构（平均间距 20 ± 6 nm），其中包含嵌入基体中的高密度 Ag 纤维（平均宽度低于 5 nm）。在共晶组分中，形成了相对粗大的结构，平均 Ag 晶粒尺寸约为 100 nm。这种双峰尺寸的银纤维的结果是超高的弯曲塑性，即拉制的线材在最外边缘可承受 59% 的弯曲应变，是其拉伸伸长率 (3.6%) 的 15 倍。在我们的弯曲试验中，动态恢复和部分再结晶更多地发生在靠近内边缘的地方而不是靠近外边缘的地方，并且主要发生在共晶成分中。高弯曲应变导致一些较粗的 Ag 纤维变得不连续并失去其原始对齐方式。这种结构演变增加了局部塑性，导致可实现的弯曲应变出乎意料地高，这在纳米尺寸、银纤维增强的高强度复合材料中是不寻常的。