过渡金属原子固溶在CeO_2中结构与力学性能研究

Elastic Properties of Transition Metal Atom in CeO_2 Solid Solution

为考察CeO_2及其固溶过渡金属原子后的力学特性,采用基于密度泛函理论(DFT)的第一性原理方法,计算了过渡金属(Ti族:Ti、Zr、Hf,V族:V、Nb、Ta)单原子置换固溶在CeO_2中的结构,进而计算CeO_2及其固溶结构的力学特性。计算结果表明,固溶后CeO_2体系力学常数(B、G、E、C11、C12)均有所增加,其中固溶Nb原子后力学性能提高比较明显。但固溶Ti、V原子后C44出现明显下降的现象。Nb原子固溶体的弹性模量明显增大,且各向异性与CeO_2相似无明显差异。较Ti、V、Ta原子在CeO_2中的置换固溶结构的弹性模量各向异性明显不同,Nb、Zr、Hf原子在CeO_2中置换固溶结构的弹性模量各向异性并不突出。通过计算CeO_2的能带和态密度,CeO_2表现非金属性,且能带结构中存在两条带隙。

The elastic properties of solid solution structure of the transition metal atomistic Ti, Zr, Hf, V, Nb and Ta in CeO2 crystal are studied with using first principle method, which is based on the density functional theory （ D^l＇）. The inves- tigation presents some results. The elastic constants （B, G, E, CH and C^2 ） of CeO~ and solid solution structure of CeO2 - M system have increased, after which the mechanical properties of CeO2 - Nb better other solid solution structure. The elastic constants of C~ of CeO2 - Ti and CeO2 - V marked decline phenomenon. The elastic modulus of solid solution CeO2 - Nb sig- nificantly increased, and anisotropy is not significant difference similar as CeO2. Also, the solid solution of Ti, V, Ta in CeO2 crystal of elastic modulus anisotropy has a significant difference. The solid solution of Nb, Zr, Hf in CeO2 crystal anisotropy of the elastic modulus are not prominent. By calculating the energy band and density of states shows that CeO2 is an insulator, and there are two band gap.