【摘要】 通过第一性原理超晶胞方法研究了氧(O)原子在体心立方(BCC)难熔金属Nb,Ta,Mo,W中不同间隙位置的占位稳定性和原子结构以及电子结构。杂质形成能结果表明,O原子占据在Nb,Ta的八面体间隙最稳定;与之相反,O原子占据在Mo,W的四面体间隙位置最稳定。进一步的,O原子在BCC难熔金属的杂质形成能由低到高的顺序为Nb<Ta<Mo<W,这表明金属中溶解氧容易顺序为Nb>Ta>Mo>W。此外,分析了O对难熔金属Nb,Ta,Mo,W原子结构的影响。利用电子结构态密度解释了氧原子在Nb,Ta八面体间隙和Mo,W四面体间隙的最稳定性原因。更多还原

【Abstract】 With first-principles calculations and supercell model,the different site occupation stability,geometric and electronic structures of oxygen(O)atom were systematically investigated in the bodycentered-cubic(BCC)Nb,Ta,Mo and W refractory metals(RMs).Impurity formation energy result shows that,the O atom prefers to occupy at octahedral(Oct)site in the BCC Nb and Ta RMs,while the O atom likes occupying at tetragonal(Tet)site for oxygen in the BCC Mo and W RMs.Furthermore,the order of impurity formation energy of oxygen atom in the RMs is Nb < Ta < Mo < W,which indicates that the stability and easy order of dissolved oxygen atom in the RMs is Nb > Ta > Mo > W.In addition,the effect of O atom on the geometric structure of RMs was discussed and their electronic structures explained that the most stable site of O is the octahedral site in Nb and Ta as well as the tetrahedral site in Mo and W.更多还原