置氢α-钛和β-钛晶体结构的第一性原理研究

First-Principles Study of α-Titanium and β-Titanium Crystal Structure

摘要:

基于第一性原理方法建立了α-钛和β-钛置氢后的晶体结构模型，优化了稳态结构。在此基础上，计算了α-钛和β-钛置氢后的体积、体积膨胀率、晶格常数与比值的变化情况。计算结果表明：置氢量对α-钛的晶轴夹角和体积膨胀影响显著，为氢化物的形成提供了必要的能量条件；置氢量低于0.2597% (质量分数)时，氢在β-钛中占据四面体间隙位，置氢量高于0.5181%时，占据八面体间隙位

关键词:第一性原理;钛;氢;晶体结构

Abstract:

The crystal structure models of α-titanium and β-titanium with hydrogen were established and the stable structure was optimized. The variation of volume, volume expansion rate, lattice constant and ratio of lattice constant for the α-titanium and β-titanium with hydrogen were calculated with help of the first principle method. The calculated results show that the hydrogen content affects the angle of crystal axe and volume expansion. Hydrogen would occupy the tetrahedral space of β-titanium at the hydrogen content below 0.2597wt% and/or the octahedral space of β-titanium at the hydrogen content above 0.2597 wt%

Key words:first principle; titanium; hydrogen; crystal structure