Metal [100] Nanowires with Negative Poisson's Ratio.
Metal [100] Nanowires with Negative Poisson's Ratio.
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DOI：
10.1038/srep27560
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发表时间：
2016-06-10
影响因子：
4.6
通讯作者：
Kim SY
中科院分区：
文献类型：
--
作者：
Ho DT;Kwon SY;Kim SY
当材料处于拉伸状态时，经常会出现材料的横向收缩现象。这是因为泊松比几乎对所有材料都是正值。泊松比是描述横向应变和外加应变之间关系的数量。据报道，有些结构和材料的泊松比为负值。然而，它们大多是在宏观尺度上的，而折返结构和刚性旋转单元是它们负泊松比行为的主要机制。在这里，我们用数值和理论证据表明，具有不对称截面的金属[100]纳米线，如矩形或椭圆，可以表现出负的泊松比行为。此外，通过在非对称纳米线中引入空穴可以进一步改善负泊松比行为。结果表明，引起纳米线内部非对称应力的表面效应是纳米线具有优异性能的主要原因。
When materials are under stretching, occurrence of lateral contraction of materials is commonly observed. This is because Poisson’s ratio, the quantity describes the relationship between a lateral strain and applied strain, is positive for nearly all materials. There are some reported structures and materials having negative Poisson’s ratio. However, most of them are at macroscale, and reentrant structures and rigid rotating units are the main mechanisms for their negative Poisson’s ratio behavior. Here, with numerical and theoretical evidence, we show that metal [100] nanowires with asymmetric cross-sections such as rectangle or ellipse can exhibit negative Poisson’s ratio behavior. Furthermore, the negative Poisson’s ratio behavior can be further improved by introducing a hole inside the asymmetric nanowires. We show that the surface effect inducing the asymmetric stresses inside the nanowires is a main origin of the superior property.