Mechanical stability of Ni and Ir under hydrostatic and uniaxial loading

0449977 - ÚFM 2016 RIV GB eng J - Článek v odborném periodiku
Řehák, Petr - Černý, Miroslav - Šob, Mojmír
Mechanical stability of Ni and Ir under hydrostatic and uniaxial loading.
Modelling and Simulation in Materials Science and Engineering. Roč. 23, č. 5 (2015), art. n. 055010. ISSN 0965-0393. E-ISSN 1361-651X
Grant CEP: GA ČR(CZ) GAP108/12/0311
Institucionální podpora: RVO:68081723
Klíčová slova: ab initio calculations * elastic stability * phonon instability * theoretical strength * hydrostatic loading * uniaxial loading
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
Impakt faktor: 1.859, rok: 2015

Two fcc crystals, Ni and Ir, are subjected to simulated isotropic and uniaxial tension along the 100 direction. Their structural stability is assessed by analyzing phonon spectra that are calculated from first principles for different values of strain. A relevant analysis of elastic stability conditions is also performed. Predicted elastic instabilities correspond well to those associated with soft phonons with vanishing wavevectors. Although most of previous studies predicted that first instabilities in crystals correspond to macroscopic (elastic) instabilities, we found soft phonons of finite wavevectors at lower strains (and stresses) during both considered loadings in the crystal of Ir. Predicted instabilities were confirmed by our models of microscopic deformation.
Trvalý link: http://hdl.handle.net/11104/0251463