To experimentally clarify the changes in structural and dynamic heterogeneities in a metallic glass (MG), Gd65Co35, by rejuvenation with temperature cycling (cryogenic rejuvenation), high-energy X-ray diffraction (HEXRD), anomalous x-ray scattering (AXS), and inelastic x-ray scattering (IXS) experiments were carried out. By repeated temperature changes between liquid N2 and room temperatures 40 times, we observed tiny but clear structural changes by HEXRD even in the first-nearest neighbor range. The partial structural information obtained by AXS revealed that slight movements of Gd and Co atoms occur in the first- and second-nearest neighbor shells around the central Gd atom. The composition heterogeneity in nanometer size is markedly increased for the Gd atoms by temperature cycling, whereas the other heterogeneities are negligible. A distinct change was detected in microscopic elastic property by IXS: The width of longitudinal acoustic excitation broadens by about 20%, indicating an increase in the elastic heterogeneity of this MG induced by thermal treatments. These static and dynamic results explicitly clarify the features of the cryogenic rejuvenation effect experimentally.

中文翻译：

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低温年轻化对 Gd-Co 金属玻璃的结构和动力学变化


为了通过温度循环回春 （cryogenic rejuvenation）、高能 X 射线衍射 （HEXRD）、异常 X 射线散射 （AXS） 和非弹性 X 射线散射 （IXS） 实验，实验阐明金属玻璃 （MG） Gd65Co35 中结构和动力学异质性的变化，进行了实验。通过在液体 N2 和室温之间重复温度变化 40 次，即使在第一最近邻范围内，我们也观察到 HEXRD 的微小但清晰的结构变化。AXS 获得的部分结构信息显示，Gd 和 Co 原子的轻微运动发生在中心Gd原子周围的第一和第二近邻壳层中。通过温度循环，Gd 原子的纳米尺寸组成异质性显着增加，而其他非均质性可以忽略不计。通过 IXS 检测到微观弹性特性的明显变化：纵向声激励的宽度扩大了约 20%，表明热处理引起的该 MG 的弹性异质性增加。这些静态和动态结果在实验上明确阐明了低温回春效应的特征。