Metals are known to exhibit mechanical behaviour at the nanoscale different to bulk samples. This transition typically initiates at the micrometre scale, yet existing techniques to produce micrometre-sized samples often introduce artefacts that can influence deformation mechanisms. Here, we demonstrate the casting of micrometre-scale aluminium single-crystal wires by infiltration of a salt mould. Samples have millimetre lengths, smooth surfaces, a range of crystallographic orientations, and a diameter D as small as 6 μm. The wires deform in bursts, at a stress that increases with decreasing D. Bursts greater than 200 nm account for roughly 50% of wire deformation and have exponentially distributed intensities. Dislocation dynamics simulations show that single-arm sources that produce large displacement bursts halted by stochastic cross-slip and lock formation explain microcast wire behaviour. This microcasting technique may be extended to several other metals or alloys and offers the possibility of exploring mechanical behaviour spanning the micrometre scale.

中文翻译：

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铸铝单晶越过了从体积到取决于尺寸的随机可塑性的极限

已知金属在纳米尺度上表现出与整体样品不同的机械性能。这种转变通常始于微米尺度，但是现有的生产微米尺度样品的技术通常会引入可能影响变形机制的伪像。在这里，我们演示了通过盐模的渗透来铸造微米级的铝单晶线。样品的长度为毫米，表面光滑，具有一定的晶体取向，直径D小至 6μm。导线突然变形，应力随着D的减小而增加。爆发次数大于200 纳米大约占线变形的50％，并且强度呈指数分布。位错动力学模拟表明，单臂源产生大的位移爆发，而随机交叉滑动和锁定形成阻止了该位移爆发，这解释了微铸丝的行为。这种微铸技术可以扩展到其他几种金属或合金，并提供探索跨越微米尺度的机械性能的可能性。