Intrinsic correlation between β-relaxation and spatial heterogeneity in a metallic glass.
Intrinsic correlation between β-relaxation and spatial heterogeneity in a metallic glass.
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DOI：
10.1038/ncomms11516
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发表时间：
2016-05-09
影响因子：
16.6
通讯作者：
Chen MW
中科院分区：
文献类型：
--
作者：
Zhu F;Nguyen HK;Song SX;Aji DP;Hirata A;Wang H;Nakajima K;Chen MW
长期以来，β弛豫被归因于玻璃中被限制在孤立区域的组成分子或原子的局部运动。然而，直接的实验证据，以支持这种空间异质性的情况下仍然失踪。在这里，我们报告的演变过程中的金属玻璃的纳米结构异质性β弛豫利用调幅动态原子力显微镜。β弛豫过程中不均匀性的连续退化可以用Kohlrausch-Williams-Watts方程很好地描述。非均质演化的特征弛豫时间和活化能与β弛豫释放过量焓的特征弛豫时间和活化能雅阁。我们的研究将β弛豫与纳米尺度的空间不均匀性联系起来，并为金属玻璃中β弛豫的结构起源提供了直接证据。 玻璃中的β-弛豫通常归因于纳米尺寸域中组成原子的受限运动，但迄今为止还没有直接的证据。在这里，Zhu等人展示了纳米尺度下空间异质性的演变与玻璃化转变点以下的β弛豫之间的相关性。
β-relaxation has long been attributed to localized motion of constituent molecules or atoms confined to isolated regions in glasses. However, direct experimental evidence to support this spatially heterogeneous scenario is still missing. Here we report the evolution of nanoscale structural heterogeneity in a metallic glass during β-relaxation by utilizing amplitude-modulation dynamic atomic force microscopy. The successive degeneration of heterogeneity during β-relaxation can be well described by the Kohlrausch–Williams–Watts equation. The characteristic relaxation time and activation energy of the heterogeneity evolution are in accord with those of excess enthalpy release by β-relaxation. Our study correlates β-relaxation with nanoscale spatial heterogeneity and provides direct evidence on the structural origins of β-relaxation in metallic glasses. Beta-relaxation in glasses is commonly attributed to the confined motions of constituent atoms in nanosized domains, but there is no direct evidence so far. Here, Zhu et al. show the correlation between the evolution of spatial heterogeneity at nanoscale and beta-relaxation below glass transition point.