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arXiv 1607.06162cond-mat.mtrl-sci
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(Cr,Ti)_3AlC_2 MAX相稳定性的实验和DFT研究

Experimental and DFT investigation of (Cr,Ti)3AlC2 MAX phases stability

Patrick A. Burr, Denis Horlait, William E. Lee

摘要:

使用实验和计算方法的协同组合,我们揭示了(Cr,Ti)3AlC 2 MAX相的不寻常的溶解度,表明它可以仅在非常低的浓度(<2at%)或在精确的Cr/(Cr+Ti)比为2/3时容纳Cr,即使当反应物的比例远离该化学计量(1/2 < Cr/(Cr+Ti)< 5/6)时。在这两个阶段中,铬专门占据4f网站,桥接碳化物层与铝层。尽管如此,(Cr 2/3 Ti 1/3)3AlC 2的特殊稳定性归因于形成强的、自旋极化的Cr-C键,这导致体积减小和c/a比的显著增加。

英文摘要:

Using a synergistic combination of experimental and computational methods, we shed light on the unusual solubility of (Cr,Ti)3AlC2 MAX phase, showing that it may accommodate Cr only at very low concentrations (<2at%) or at the exact Cr/(Cr+Ti) ratio of 2/3, even when the ratio of reactants is far from this stoichiometry (1/2 < Cr/(Cr+Ti) < 5/6). In both phases Cr exclusively occupies the 4f sites, bridging carbide layers with the Al layer. Despite this, the peculiar stability of (Cr2/3Ti1/3)3AlC2 is attributed to the formation of strong, spin-polarised Cr-C bonds, which result in volume reduction and marked increase in c/a ratio.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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