Dynamic creation and evolution of gradient nanostructure in single-crystal metallic microcubes
Dynamic creation and evolution of gradient nanostructure in single-crystal metallic microcubes
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DOI：
10.1126/science.aag1768
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发表时间：
2016-10-21
期刊：
影响因子：
56.9
通讯作者：
Thomas, Edwin L.
中科院分区：
文献类型：
--
作者：
Thevamaran, Ramathasan;Lawal, Olawale;Thomas, Edwin L.
我们演示了在最初接近无缺陷的单晶银微立方体中，极端梯度纳米颗粒结构的动态产生和随后的静态演化。极端的纳米结构转变是由高应变率、应变梯度和微立方体对不可穿透的衬底的高速碰撞中的再结晶造成的。我们在自下而上的种子生长过程中合成了银微立方体，并使用先进的激光诱导弹丸撞击测试设备以超音速(类似于400米/秒)选择性地发射它们。我们的研究对高速碰撞产生的基本变形机制以及晶体和样品形状对称性的影响提供了新的见解。在我们的实验中产生的纳米结构转变展示了开发梯度纳米颗粒金属的有希望的途径，用于要求高强度和高韧性的工程应用--例如，在飞机和航天器的结构部件中。
We demonstrate the dynamic creation and subsequent static evolution of extreme gradient nanograined structures in initially near-defect-free single-crystal silver microcubes. Extreme nanostructural transformations are imposed by high strain rates, strain gradients, and recrystallization in high-velocity impacts of the microcubes against an impenetrable substrate. We synthesized the silver microcubes in a bottom-up seed-growth process and use an advanced laser-induced projectile impact testing apparatus to selectively launch them at supersonic velocities (similar to 400 meters per second). Our study provides new insights into the fundamental deformation mechanisms and the effects of crystal and sample-shape symmetries resulting from high-velocity impacts. The nanostructural transformations produced in our experiments show promising pathways to developing gradient nanograined metals for engineering applications requiring both high strength and high toughness-for example, in structural components of aircraft and spacecraft.