Microscopic characterization of structural relaxation and cryogenic rejuvenation in metallic glasses
Microscopic characterization of structural relaxation and cryogenic rejuvenation in metallic glasses
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DOI：
10.1016/j.actamat.2018.10.036
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发表时间：
2019-02-01
期刊：
影响因子：
9.4
通讯作者：
Atzmon, M.
中科院分区：
文献类型：
--
作者：
Lei, T. J.;DaCosta, L. Rangel;Atzmon, M.
已有报道称，在室温和液氮温度之间循环处理可改善金属玻璃的塑性，这归因于热膨胀系数不均匀导致的返老性。然而，具体的微观效应仍不清楚。本文主要研究了室温老化和低温循环的微观效应。对La70Cu15Al15和La70Cu15Al15金属玻璃进行了不同时间的时效处理，其中一些玻璃还进行了低温循环。然后用准静态滞弹性松弛测量来表征七个数量级的时间常数谱。整体滞弹性应变随时效时间的延长而减小，但受低温循环的影响不明显。另一方面，虽然衰老也会导致特征时间常数的增加，但骑自行车可以逆转这种影响。这些新的细节揭示了结构松弛和回春对剪切转换带性质的影响。皇冠版权(C)2018由爱思唯尔有限公司代表Acta Materialia Inc.出版。保留所有权利。
Plasticity improvement in metallic glasses resulting from cycling treatment between room and liquid nitrogen temperature has been reported and attributed to rejuvenation due to a non-uniform thermal expansion coefficient. However, the detailed microscopic effect is still unclear. The present study focuses on the microscopic effect of room-temperature ageing and cryogenic cycling. La70Cu15Al15 and La70Cu15Al15 metallic glasses were subjected to varying ageing times, after which some were also cryogenically cycled. Quasi-static anelastic relaxation measurements were then employed to characterize the time-constant spectra over seven orders of magnitude. The overall anelastic strain decreases with increasing ageing time, but is not noticeably affected by cryogenic cycling. On the other hand, while ageing also causes an increase in characteristic time constants, cycling reverses this effect. The new details shed light on the effect of structural relaxation and rejuvenation on the properties of shear transformation zones. Crown Copyright (C) 2018 Published by Elsevier Ltd on behalf of Acta Materialia Inc. All rights reserved.