Shear transformation zone analysis of anelastic relaxation of a metallic glass reveals distinct properties of α and β relaxations
Shear transformation zone analysis of anelastic relaxation of a metallic glass reveals distinct properties of α and β relaxations
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金属玻璃滞弹性弛豫的剪切转变区分析揭示了 α 和 β 弛豫的不同特性
DOI：
10.1103/physreve.100.033001
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发表时间：
2019
影响因子：
2.4
通讯作者：
Atzmon, M.
中科院分区：
文献类型：
--
作者：
Lei, T. J.;Rangel DaCosta, L.;Liu, M.;Wang, W. H.;Sun, Y. H.;Greer, A. L.;Atzmon, M.
据观察，在动态机械响应中具有明显高频β弛豫的金属玻璃表现出很大的塑性。由于它们的原子结构无序，确定其弛豫行为的微观机制具有挑战性。对金属玻璃进行了超过 10 个数量级的准静态滞弹性弛豫测量，金属玻璃表现出很强的 β 弛豫。相应的时间常数光谱是根据数据计算得出的，它们包含一系列对应于剪切变换区 (STZ) 原子量化层次结构的峰，其中 α 和 β 弛豫均与 STZ 模型一致。观察到峰之间的两种不同的激活体积增量模式，表明对应于 α 与 β 弛豫的 STZ 中涉及不同元素。室温结构松弛显着影响前者，但不影响后者。
Metallic glasses with pronounced high-frequency β relaxation in their dynamic-mechanical response have been observed to exhibit large plasticity. Due to their disordered atomic structure, it is challenging to identify the microscopic mechanisms of their relaxation behavior. Quasistatic anelastic relaxation measurements have been performed over 10 orders of magnitude of time onmetallic glass, which exhibits a strong β relaxation. The corresponding time-constant spectra were computed from the data—they contain a series of peaks corresponding to an atomically quantized hierarchy of shear transformation zones (STZs), where both the α and β relaxations are consistent with the STZ model. Two different regimes of activation-volume increment between the peaks are observed, suggesting the involvement of different elements in STZs corresponding to α vs β relaxations. Room-temperature structural relaxation significantly affects the former but not the latter.