钛-氢体系晶体结构和能量的第一原理计算

来源期刊:中国有色金属学报2008年第3期

论文作者:韩秀丽 王清 孙东立 张红星

文章页码:523 - 523

关键词:钛-氢体系;第一原理;晶体结构;结合能;溶解热;

Key words:Ti-H system; first-principles; crystal structure; binding energy; solution heat

摘    要:

采用基于密度泛函理论的第一原理赝势平面波方法研究了不同钛-氢摩尔比的α-Ti-H和β-Ti-H晶体的稳态几何结构,进行了稳态晶体的总能量计算。结果表明:氢引起α-Ti和β-Ti晶格点阵畸变,晶体体积膨胀。计算得到的不同钛-氢摩尔比的α-Ti-H和β-Ti-H晶体结合能分别小于α-Ti和β-Ti晶体结合能,表明氢原子降低了α-Ti和β-Ti晶体的结合能。氢原子在β-Ti晶体中的占位随氢含量变化,低氢含量时易占据四面体间隙位置,高氢含量时倾向于占据八面体间隙位置。

Abstract: The equilibrium structures and total energies of α-Ti-H and β-Ti-H crystals with different mole ratios of Ti to H were calculated with the first-principles method based on plane-wave pseudopotential and density function theory. The calculated results show that hydrogen causes the lattice distortion and volume expansion of α-Ti and β-Ti crystals. The calculated binding energies of α-Ti-H and β-Ti-H crystals with different mole ratios of Ti to H are less than those of pure α-Ti and β-Ti crystals, respectively. It reveals that hydrogen atom reduces the binding energies of α-Ti and β-Ti crystals. The calculation results show that the site preference of hydrogen in β-Ti crystal varies with hydrogen content varyiing. Hydrogen is inclined to enter the tetrahedral interstitial site in β-Ti-H crystal with low hydrogen content, and hydrogen is disposed to occupy the octahedral site in β-Ti-H crystal with high hydrogen content.

基金信息:国家自然科学基金资助项目

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