Entropic effect on creep in nanocrystalline metals
Entropic effect on creep in nanocrystalline metals
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DOI：
10.1016/j.actamat.2013.03.026
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发表时间：
2013-06
期刊：
影响因子：
9.4
通讯作者：
Yunjiang Wang;A. Ishii;S. Ogata
中科院分区：
文献类型：
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作者：
Yunjiang Wang;A. Ishii;S. Ogata
我们用分子动力学方法研究了纳米晶金属蠕变过程中的熵效应。我们的模拟表明，激活熵可能有助于许多数量级的倍增因子的稳态蠕变速率。活化熵与焓的关系服从经验Meyer-Neldel补偿规则。位错形核蠕变激活体积随温度的升高而减小，这与实验结果吻合较好。该研究开辟了一条途径，定量讨论熵的各种热激活变形的纳米晶体。
We report a significant entropic effect on creep of nanocrystalline metal using molecular dynamics. Our simulations reveal that the activation entropy may contribute a multiplicative factor of many orders of magnitude to the steady-state creep rate. The relationship between activation entropy and enthalpy obeys an empirical Meyer–Neldel compensation rule. The activation volume is found to decrease with increasing temperature for dislocation nucleation creep, which agrees well with experimental results. The study opens up an avenue for quantitatively discussing the entropic effects on various thermally activated deformations in nanocrystals.