Abstract First principles calculations based on different substitution models are performed to investigate the structural, elastic, thermodynamic, and electronic properties of body-centered cubic (bcc) Zr-Nb alloy which has great potential in biomedicine and nuclear power in the whole interval of concentration. The results show that the calculated lattice parameters decrease linearly with the increase of Nb concentration which are in good accordance with the experimental and other first principles calculations. The structure of bcc Zr is unstable at 0 K, and Nb additions can improve bcc Zr-Nb solid solution mechanical stability. Bcc Zr-Nb disordered solid solution with the relaxed structure deviate from the perfect bcc lattice position and transform into a more stable non-β phase, however, the atoms of the ordered solid solution occupy maintains the ideal sites of bcc structure. The elastic constants Cij, elastic modulus (B, G, E), Poisson’s ratio and elastic anisotropy also have been calculated. When the structure of bcc Zr-Nb alloy is stable, the Nb addition can increase the elastic modulus, B/G ration and Poisson's ratio which will improve the ductility of alloy. The electronic properties have been investigated based on density of states and charge density difference. The bcc Zr-Nb alloy electronic structure is usually composed of metal bonds and covalent bonds, and metal bonds is dominated. Zr50Nb50 has the highest covalent bond ratio. Finally, the thermodynamic properties are evaluated by quasi-Debye model.

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bcc Zr-Nb 合金的结构、机械、电子和热力学性能：第一性原理研究

摘要 基于不同的替代模型进行第一性原理计算，研究在整个浓度区间内具有巨大生物医学和核电潜力的体心立方（bcc）Zr-Nb合金的结构、弹性、热力学和电子特性。 . 结果表明，计算的晶格参数随着Nb浓度的增加而线性下降，这与实验和其他第一性原理计算结果非常吻合。bcc Zr 的结构在 0 K 时不稳定，添加 Nb 可以提高 bcc Zr-Nb 固溶体的机械稳定性。具有松弛结构的 Bcc Zr-Nb 无序固溶体偏离完美的 bcc 晶格位置并转变为更稳定的非β相，然而，有序固溶体占据的原子保持了 bcc 结构的理想位点。还计算了弹性常数 Cij、弹性模量（B、G、E）、泊松比和弹性各向异性。当bcc Zr-Nb合金的结构稳定时，Nb的加入可以提高弹性模量、B/G比和泊松比，从而提高合金的延展性。已经基于状态密度和电荷密度差异研究了电子性质。bcc Zr-Nb合金电子结构通常由金属键和共价键组成，以金属键为主。Zr50Nb50 具有最高的共价键比率。最后，通过准Debye模型评估热力学性质。泊松比和弹性各向异性也已计算。当bcc Zr-Nb合金的结构稳定时，Nb的加入可以提高弹性模量、B/G比和泊松比，从而提高合金的延展性。已经基于状态密度和电荷密度差异研究了电子性质。bcc Zr-Nb合金电子结构通常由金属键和共价键组成，以金属键为主。Zr50Nb50 具有最高的共价键比率。最后，通过准Debye模型评估热力学性质。泊松比和弹性各向异性也已计算。当bcc Zr-Nb合金的结构稳定时，Nb的加入可以提高弹性模量、B/G比和泊松比，从而提高合金的延展性。已经基于状态密度和电荷密度差异研究了电子性质。bcc Zr-Nb合金电子结构通常由金属键和共价键组成，以金属键为主。Zr50Nb50 具有最高的共价键比率。最后，通过准Debye模型评估热力学性质。已经基于状态密度和电荷密度差异研究了电子性质。bcc Zr-Nb合金电子结构通常由金属键和共价键组成，以金属键为主。Zr50Nb50 具有最高的共价键比率。最后，通过准Debye模型评估热力学性质。已经基于状态密度和电荷密度差异研究了电子性质。bcc Zr-Nb合金电子结构通常由金属键和共价键组成，以金属键为主。Zr50Nb50 具有最高的共价键比率。最后，通过准Debye模型评估热力学性质。