Force-matched empirical potential for martensitic transitions and plastic deformation in Ti-Nb alloys

摘要

A force-matched spline-based empirical potential based on the modified embedded-atom method is fit to an extensive database of highly converged density functional theory calculations for titanium-niobium alloys with an evolutionary algorithm. Consistency with experiment and existing models is verified through calculations of structural, elastic, and thermal properties. The potential is used to study the effects of alloying on elastic properties, the martensite phase of Ti-rich alloys, and the α-β and β-ω transformations. Stress- and temperature-induced martensitic transitions are demonstrated in Ti-25 at. % Nb by NPT simulation. Last, the effect of alloying on screw dislocations in hcp-Ti and bcc-Nb is analyzed at 5 at. % solute content with the fitted potential.