First-principles study of binary bcc alloys using special quasirandom structures
First-principles study of binary bcc alloys using special quasirandom structures
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DOI：
10.1103/physrevb.69.214202
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发表时间：
2004-06-01
影响因子：
3.7
通讯作者：
Liu, ZK
中科院分区：
文献类型：
--
作者：
Jiang, C;Wolverton, C;Liu, ZK
本文给出了A（1-x）B（x）bcc替位合金在x=0.25，0.50和0.75时的三种16原子特殊准无规结构（SQS）。该结构具有本地对和multisite相关功能，模仿相应的随机体心立方合金。这些SQS的引入允许体心立方固溶体的第一原理计算的可能性，即使是那些具有显着的尺寸失配或原子弛豫。我们已经通过第一性原理计算在Mo-Nb，Ta-W和Cr-Fe系统中测试了我们的SQS，其中观察到bcc固溶体在整个组成范围内是稳定的。我们的第一性原理SQS结果提供的形成的bcc合金，这些bcc合金的平衡晶格参数和磁矩与文献中大多数现有的实验数据令人满意地同意。为了理解体心立方固溶体中原子的弛豫行为，我们还研究了无规体心立方合金中的最近邻键长分布。所提出的体心立方SQS具有普遍性，可应用于其它二元体心立方合金。
We present three 16-atom special quasirandom structures (SQS's) for A(1-x)B(x) bcc substitutional alloys at compositions x=0.25, 0.50 and 0.75, respectively. The structures possess local pair and multisite correlation functions that mimic those of the corresponding random bcc alloy. The introduction of these SQS's allows for the possibility of first-principles calculations of bcc solid solutions, even those with significant size-mismatch or atomic relaxation. We have tested our SQS's via first-principles calculations in the Mo-Nb, Ta-W and Cr-Fe systems, in which the bcc solid solution is observed to be stable over the whole composition range. Our first-principles SQS results provide formation enthalpies, equilibrium lattice parameters and magnetic moments of these bcc alloys which agree satisfactorily with most existing experimental data in the literature. In an effort to understand the atomic relaxation behavior in bcc solid solutions, we have also investigated the nearest neighbor bond length distributions in the random bcc alloys. The proposed bcc SQS's are quite general and can be applied to other binary bcc alloys.