%0 Journal Article
%T Structural instabilities and mechanical properties of U$_2$Mo from first principles calculations
%A Ben-Qiong Liu
%A Xiao-Xi Duan
%A Guang-Ai Sun
%A Jin-Wen Yang
%A Tao Gao
%J Physics
%D 2014
%I arXiv
%R 10.1039/C4CP05483K
%X 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.
%U http://arxiv.org/abs/1411.0493v1