Cálculo del esfuerzo ideal de metales nobles mediante primeros principios en la dirección $\langle$100$\rangle$

Abstract

We present calculations of the ideal strength on the $\langle$100$\rangle$ direction for noble metals (Cu, Ag and Au), by means of first principles calculations. First, we obtain the structural parameters (cell parameters, bulk modulus) for each studied metal. We deform on the $\langle$100$\rangle$ direction calculating the total energy and the stress tensor through the Hellman-Feynman theorem, by the relaxation of the unit cell in the perpendicular directions to the deformation one. The calculated cell constants differ 1.3% from experimental data. The maximum ideal strength are 29.6, 17 and 19 GPa for Cu, Ag and Au respectively. Meanwhile, the calculated elastic modulus are 106 (Cu), 71 (Ag), and 45 GPa (Au) and are in agreement with the experimental values for polycrystalline samples. The values of maximum strength are explained by the optimum volume values due to the atomic radius size for each element.