Linking macroscopic rejuvenation to nano-elastic fluctuations in a metallic glass
Linking macroscopic rejuvenation to nano-elastic fluctuations in a metallic glass
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DOI：
10.1016/j.actamat.2017.07.043
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发表时间：
2017-10
期刊：
影响因子：
9.4
通讯作者：
Perry Ross;S. Küchemann;P. Derlet;H. Yu;W. Arnold;P. Liaw;K. Samwer;R. Maaß
中科院分区：
文献类型：
--
作者：
Perry Ross;S. Küchemann;P. Derlet;H. Yu;W. Arnold;P. Liaw;K. Samwer;R. Maaß
金属玻璃在一定长度尺度下是结构不均匀的。在这里，我们演示了如何弹性异质性的变化响应于宏观循环，但弹性，加载协议。局部弹性性质的波动在空间上解决了整个表面的散装样品通过评估纳米级的接触共振的原子力显微镜。研究结果表明，由于加载的纳米弹性波动显着增加。这些波动的分布对称地扩大了几乎三倍，揭示了原子无序结构如何在纳米尺度上进一步偏离平衡。宏观上，应力驱动的弹性不均匀性导致再生，并因此导致块体金属玻璃的新的结构状态，其特征在于在加热和机械软化期间释放更高的能量。这些结果表明，金属玻璃中的宏观储能可能与纳米尺度弹性波动的发展有关。
Metallic glasses are structurally heterogeneous below a certain length scale. Here we demonstrate how elastic heterogeneities change in response to a macroscopic cyclic, but elastic, loading protocol. Fluctuations in local elastic properties are spatially resolved across the surface of a bulk sample by evaluating nano-scale contact resonances of an atomic force microscope. The findings indicate a significant increase in nano-elastic fluctuations due to loading. The distribution of these fluctuations broadens symmetrically and almost three fold, revealing how the atomically disordered structure is driven further out of equilibrium at the nano-scale. Macroscopically, the stress-driven elastic heterogeneities lead to a rejuvenation and therefore a new structural state of the bulk metallic glass, characterized by a higher energy release during heating and mechanical softening. These results show how macroscopic energy storage in metallic glasses may be linked to the development of nano-scale elastic fluctuations.