Nonlinear elastic properties of the polycrystalline refractory metals at Megabar pressures: Theoretical approach

Publication date: 5 February 2018
Source:Materials & Design, Volume 139
Author(s): O.M. Krasilnikov, A.V. Lugovskoy, Yu.Kh. Vekilov, Yu.E. Lozovik
We present the theoretical technique for the calculation of nonlinear elastic properties of polycrystals in the presence of hydrostatic pressure. For the isotropic aggregates of single-crystal grains with cubic or hexagonal structures at given pressure we define the Lamé constants and express them through the second and third order single-crystal elastic constants. We present the calculated third order Lamé elastic modules of polycrystalline W, Mo and Ru in the pressure range of 0–600GPa. The results agree with available experimental data. The obtained values can be used for the prediction of properties for these materials at high pressures and finite deformations. We show, that the methodology can be effectively used with ab initio calculations techniques to obtain the data on elastic properties of practical importance.

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