Sluggish diffusion in Co-Cr-Fe-Mn-Ni high-entropy alloys
Sluggish diffusion in Co-Cr-Fe-Mn-Ni high-entropy alloys
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DOI：
10.1016/j.actamat.2013.04.058
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发表时间：
2013-08-01
期刊：
影响因子：
9.4
通讯作者：
Yeh, J. -W.
中科院分区：
文献类型：
--
作者：
Tsai, K. -Y.;Tsai, M. -H.;Yeh, J. -W.
熔体扩散动力学是高熵合金优异性能的重要贡献者。然而，在高熵合金中的扩散动力学从来没有被直接探讨过。本文采用扩散偶法测定了Co、Cr、Fe、Mn和Ni在理想固溶态Co-Cr-Fe-Mn-Ni合金中的扩散参数。这些参数进行了比较，在各种传统的面心立方金属。结果表明，Co-Cr-Fe-Mn-Ni合金中的扩散系数确实低于参考金属中的扩散系数。相应地，高熵合金中的激活能高于参比金属中的激活能。此外，归一化活化能的变化趋势与基体中组成元素的数量呈正相关。提出了一个准化学模型来分析晶格势能在不同基质中的涨落，并解释了所观察到的活化能的变化趋势。晶格势能的波动越大，产生的原子陷阱和块越显著，导致更高的激活能，从而解释了在高熵合金中的缓慢扩散。(C)2013 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Sluggish diffusion kinetics is an important contributor to the outstanding properties of high-entropy alloys. However, the diffusion kinetics in high-entropy alloys has never been probed directly. Here, the diffusion couple method was used to measure the diffusion parameters of Co, Cr, Fe, Mn and Ni in ideal-solution-like Co-Cr-Fe-Mn-Ni alloys. These parameters were compared with those in various conventional face-centered cubic metals. The results show that the diffusion coefficients in the Co-Cr-Fe-Mn-Ni alloys are indeed lower than those in the reference metals. Correspondingly, the activation energies in the high-entropy alloys are higher than those in the reference metals. Moreover, the trend of the normalized activation energy is positively related to the number of composing elements in the matrix. A quasi-chemical model is proposed to analyze the fluctuation of lattice potential energy in different matrices and to explain the observed trend in activation energies. Greater fluctuation of lattice potential energy produces more significant atomic traps and blocks, leading to higher activation energies, and thus accounts for the sluggish diffusion in high-entropy alloys. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.