Ab initio study of interacting lattice vibrations and stabilization of the beta phase in Ni-Ti shape-memory alloy

0349765 - ÚFM 2011 RIV US eng J - Journal Article
Souvatzis, P. - Legut, Dominik - Eriksson, M. - Katsnelson, M.I.
Ab initio study of interacting lattice vibrations and stabilization of the beta phase in Ni-Ti shape-memory alloy.
Physical Review. B. Roč. 81, č. 9 (2010), 092201/1-092201/4. ISSN 1098-0121
Institutional research plan: CEZ:AV0Z20410507
Keywords : NiTi * ab initio * phonon * anharmonicity * stabilization of beta phase
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.772, year: 2010

Lattice dynamical methods used to predict phase transformations in crystals typically evaluate the harmonic phonon spectra and therefore do not work in frequent and important situations where the crystal structure is unstable in the harmonic approximation, such as the beta structure when it appears as a high-temperature phase of the shape memory alloy Ni-Ti. Here it is shown by self-consistent ab initio lattice dynamical calculations that the critical temperature for the premartensitic R-to-beta phase transformation in Ni-Ti can be effectively calculated with good accuracy, and that the beta phase is a result primarily of the stabilizing interaction between different lattice vibrations.
Permanent Link: http://hdl.handle.net/11104/0189917