Structural evolution during the sub-Tg relaxation of hyperquenched metallic glasses
Structural evolution during the sub-Tg relaxation of hyperquenched metallic glasses
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DOI：
10.1063/1.3447373
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发表时间：
2010-06
影响因子：
4
通讯作者：
Lina Hu;Chunzhi Zhang;Y. Yue
中科院分区：
文献类型：
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作者：
Lina Hu;Chunzhi Zhang;Y. Yue
报道了超快冷La55Al25Ni20玻璃亚Tg驰豫过程中的结构特征。亚Tg驰豫与中程有序结构的变化有关，表现为在X射线衍射谱中出现预峰。这种结构变化可能是金属玻璃中Johari-Goldstein弛豫的根源。在虚化温度低于604K和高于604K的玻璃中，预峰的演化机制是不同的。根据原子键亏损模型，进一步讨论了La中心团簇中原子的协同运动。
We report the structural characteristics during the sub-Tg relaxation in hyperquenched La55Al25Ni20 glasses. The sub-Tg relaxation is associated with the structural change in intermediate range order, as manifested by the appearance of a prepeak in the x-ray diffraction spectrum. Such structural change could be the source of the Johari–Goldstein relaxation in metallic glasses. The mechanism governing the evolution of the prepeak is different between the glasses with the fictive temperature below 604 K and those above 604 K. Cooperative motion of atoms in La-centered clusters was further discussed in terms of the atomic bond deficiency model.