Abstract As so far, the investigation and application of transition metal silicon-based materials have attracted wide attention. Tantalum-based silicides are one of the most important silicon-based high-temperature materials. But the brittle behavior hinders their wide applications. Here, the influence of vacancies on mechanical properties, brittle/ductile behavior and electronic properties of Ta5Si3 desilicides has been investigated using the first-principles calculations. The vacancy formation energy, elastic constants, elastic moduli, brittle/ductile behavior and electronic behavior of the perfect Ta5Si3 and Ta5Si3 with vacancies were comparatively calculated and discussed, respectively. The thermodynamic data and phonon dispersions demonstrate that the available Ta vacancies in Ta5Si3 can exhibit the better stability than Si atomic vacancies in Ta5Si3 desilicides. In addition, although the vacancies weaken the hardness of the parent Ta5Si3, the vacancies improve the brittle behavior of the parent Ta5Si3. Especially, the Ta-Va1 vacancy in Ta5Si3 induced brittle-to-ductile transition for parent Ta5Si3 desilicides. The electronic structures explain the mechanism of the different vacancies effect on mechanical properties.

中文翻译：

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从第一性原理计算空位缺陷对TaSi (5/3) 脱硅化物弹性和电子特性的影响

摘要 目前，过渡金属硅基材料的研究和应用引起了广泛关注。钽基硅化物是最重要的硅基高温材料之一。但脆性行为阻碍了它们的广泛应用。在这里，使用第一性原理计算研究了空位对 Ta5Si3 脱硅化物的机械性能、脆/韧性行为和电子性能的影响。分别比较计算和讨论了具有空位的完美Ta5Si3和Ta5Si3的空位形成能、弹性常数、弹性模量、脆/塑性行为和电子行为。热力学数据和声子色散表明，Ta5Si3 中可用的 Ta 空位比 Ta5Si3 脱硅化物中的 Si 原子空位表现出更好的稳定性。此外，虽然空位削弱了母体 Ta5Si3 的硬度，但空位改善了母体 Ta5Si3 的脆性行为。特别是，Ta5Si3 中的 Ta-Va1 空位诱导了母体 Ta5Si3 脱硅化物的脆韧转变。电子结构解释了不同空位对机械性能影响的机制。