Free Energy Generalization of the Peierls Potential in Iron
Free Energy Generalization of the Peierls Potential in Iron
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DOI：
10.1103/physrevlett.111.095502
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发表时间：
2013-08-27
影响因子：
8.6
通讯作者：
Marian, J.
中科院分区：
文献类型：
--
作者：
Gilbert, M. R.;Schuck, P.;Marian, J.
在体心立方（bcc）晶体中，1/2< 111 >螺旋位错表现出高的内在晶格摩擦作为其非平面核心结构的结果，这导致了周期性的能量景观被称为Peierls势U-P。决定塑性流动的主要特征，包括其应力和温度依赖性，可以直接从这个潜在的，因此它的重要性。在这封信中，我们使用热力学积分提供了一个完整的热力学扩展体心立方铁的U-P。我们计算Peierls自由能路径作为应力和温度的函数，并表明临界应力消失在700 K，提供定性的元素，解释在非热极限的塑性行为。
In body-centered-cubic (bcc) crystals, 1/2 < 111 > screw dislocations exhibit high intrinsic lattice friction as a consequence of their nonplanar core structure, which results in a periodic energy landscape known as the Peierls potential U-P. The main features determining plastic flow, including its stress and temperature dependences, can be derived directly from this potential, hence its importance. In this Letter, we use thermodynamic integration to provide a full thermodynamic extension of U-P for bcc Fe. We compute the Peierls free energy path as a function of stress and temperature and show that the critical stress vanishes at 700 K, supplying the qualitative elements that explain plastic behavior in the athermal limit.