H杂质在Mo-Ta晶格中成键机制的研究

Study on the Bonding Mechanism of H Impurity in the Mo-TA Lattice

Mo-Ta合金作为一种有高熔点、抗辐照等特点的材料,被视为聚变工程中制造第一壁的潜在材料。目前有关Mo-Ta合金与H杂质相互作用的研究还不完善,本文研究了H杂质在体心立方Mo53Ta_(1)合金中间隙位置的成键机制。通过基于密度泛函的第一性原理方法,通过Material Studio的CASTEP(Cambridge Serial Total Energy Package)模块计算了Mo53Ta_(1)-H体系的溶解能,态密度与布居数。溶解能计算结果表明:H原子在Mo-Ta合金中更倾向于存在与四面体间隙位置;通过分波态密度与布居数,分析了H、Mo、Ta之间不同电子轨道间电子转移情况与不同原子间的成键情况。得出Mo、Ta间为金属键,H与Ta和Mo之间存在共价作用,且H与Ta之间的共价作用更强。

As a kind of material with high melting point and anti-irradiation,the Mo-TA alloy is regarded as a potential material for making the first wall in fusion engineering.At present,the study on the interaction between the Mo-Ta alloy and H impurity is not perfect.In this paper,the bonding mechanism of H impurity in body centered cubic Mo53Ta_(1)alloy is studied.The solution energy,density of states and population of Mo53Ta_(1)-H system were calculated by CASTEP module of the Material Studio.The calculated results of solution energy show that H atoms are more likely to exist in the tetrahedron interstitial sites in the Mo-Ta alloy.The electron transfer between different electron orbitals of H,Mo and Ta and the bonding between different atoms are analyzed by means of density of states and population.It is concluded that Mo and Ta are metal bonds,H has covalent interaction with Ta and Mo,and the covalent interaction between H and Ta is stronger.