Structural instabilities and mechanical properties of U2Mo from first principles calculations

作者：Liu, Ben-Qiong^*; Duan, Xiao-Xi; Sun, Guang-Ai; Yang, Jin-Wen; Gao, Tao

来源：Physical Chemistry Chemical Physics, 2015, 17(6): 4089-4095.

DOI：10.1039/c4cp05483k

• THERMO-PHYSICAL PROPERTIES
• URANIUM-MOLYBDENUM ALLOYS
• TOTAL-ENERGY CALCULATIONS
• DEFORMATION
• METALS
• PHASE
• MO

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 U2Mo with the C11(b) structure. In contrast to previous theoretical studies, we show that the 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 U2Mo are performed along the [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 a tension of 18-28 GPa, which indicates that the ductile U2Mo alloy will fail by shear rather than by tension.

• 出版日期2015
• 单位中国工程物理研究院核物理与化学研究所; 中国工程物理研究院; 中国工程物理研究院激光聚变研究中心; 四川大学