Department of Mechanical Engineering and Materials Science and Department of Physics, Duke University, Durham, North Carolina 27708, USA.
J Am Chem Soc. 2010 Apr 7;132(13):4830-3. doi: 10.1021/ja9105623.
Predicting from first-principles calculations whether mixed metallic elements phase-separate or form ordered structures is a major challenge of current materials research. It can be partially addressed in cases where experiments suggest the underlying lattice is conserved, using cluster expansion (CE) and a variety of exhaustive evaluation or genetic search algorithms. Evolutionary algorithms have been recently introduced to search for stable off-lattice structures at fixed mixture compositions. The general off-lattice problem is still unsolved. We present an integrated approach of CE and high-throughput ab initio calculations (HT) applicable to the full range of compositions in binary systems where the constituent elements or the intermediate ordered structures have different lattice types. The HT method replaces the search algorithms by direct calculation of a moderate number of naturally occurring prototypes representing all crystal systems and guides CE calculations of derivative structures. This synergy achieves the precision of the CE and the guiding strengths of the HT. Its application to poorly characterized binary Hf systems, believed to be phase-separating, defines three classes of alloys where CE and HT complement each other to uncover new ordered structures.
从第一性原理计算预测混合金属元素是分离还是形成有序结构，是当前材料研究的主要挑战。在实验表明潜在晶格得到保留的情况下，可以使用团簇展开（CE）和各种详尽评估或遗传搜索算法来部分解决这个问题。最近，进化算法被引入到搜索固定混合物组成的稳定非晶格结构中。一般的非晶格问题仍然没有解决。我们提出了一种 CE 和高通量从头计算（HT）的综合方法，适用于组成元素或中间有序结构具有不同晶格类型的二元系统的全组成范围。HT 方法通过直接计算代表所有晶体系统的适度数量的自然出现原型来替代搜索算法，并指导衍生结构的 CE 计算。这种协同作用实现了 CE 的精度和 HT 的指导强度。它在特征较差的二元 Hf 系统中的应用，被认为是相分离的，定义了三类合金，其中 CE 和 HT 相互补充，揭示了新的有序结构。
