Zhang Xudong, Dong Tianhui, Ma He, Yu Hui, Li Xiaoyou, Wang Feng
School of Science, Shenyang University of Technology, Shenyang, 110870, China.
School of Science, Shenyang University of Technology, Shenyang, 110870, China.
J Mol Graph Model. 2020 Jul;98:107600. doi: 10.1016/j.jmgm.2020.107600. Epub 2020 Mar 25.
As so far, the development and application prospects of transition metal silicon-based materials have received the considerable attention. V-Si silicides are one of the most important silicon-based high-temperature materials. Brittle behavior hinders their wide application. In present work, the influence of vackancies on mechanical properties, brittle/ductile behavior and electronic properties of VSi silicides is studied using the first-principles calculations. The vacancy formation energy, elastic constants, elastic modulus, brittle/ductile behavior and electronic behavior of the perfect VSi and VSi with vacancies were comparatively calculated and discussed, respectively. The thermodynamic data and phonon frequencies demonstrate that the VSi with different vacancies can exhibit the structural stability. Although the vacancies weaken the hardness of VSi, the vacancies improve the brittle behavior of the parent VSi. Especially, the Si and Si vacancies in VSi induced brittle-to-ductile transition for VSi desilicides. The electronic structures explain the mechanism of the difference of mechanical properties for different vacancies.
到目前为止，过渡金属硅基材料的发展及应用前景受到了广泛关注。V-Si硅化物是最重要的硅基高温材料之一。脆性行为阻碍了它们的广泛应用。在本工作中，利用第一性原理计算研究了空位对VSi硅化物力学性能、脆/韧性行为及电子性能的影响。分别对比计算并讨论了完美VSi和有空位的VSi的空位形成能、弹性常数、弹性模量、脆/韧性行为及电子行为。热力学数据和声子频率表明，具有不同空位的VSi可表现出结构稳定性。虽然空位会削弱VSi的硬度，但空位改善了母体VSi的脆性行为。特别是，VSi中的Si和Si空位导致VSi脱硅化物发生脆韧转变。电子结构解释了不同空位力学性能差异的机制。
