1. Structural instabilities and mechanical properties of U$_2$Mo from first principles calculations
- Author
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Liu, Ben-Qiong, Duan, Xiao-Xi, Sun, Guang-Ai, Yang, Jin-Wen, and Gao, Tao
- Subjects
Condensed Matter - Materials Science - Abstract
We perform detailed first principles calculations of the structural parameters at zero pressure and high pressure, the elastic properties, phonon dispersion relation, and ideal strengths of U$_2$Mo with $C11_b$ structure. In contrast to previous theoretical studies, we show that this $I4/mmm$ structure is indeed a mechanically and dynamically unstable phase, which is confirmed by the negative elastic constant $C_{66}$ as well as the imaginary phonon modes observed along the $\Sigma_1$-N-P line. The calculations of ideal strengths for U$_2$Mo are performed along [100], [001], and [110] directions for tension and on (001)[010] and (010)[100] slip systems for shear load. The ideal shear strength is about 8.1 GPa, much smaller than tension of 18-28 GPa, which indicates that the ductile U$_2$Mo alloy will fail by shear rather than by tension., Comment: 7 pages, 8 figures, 4 tables
- Published
- 2014
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