Density-functional theory forces, stresses and energies comprise a database from which the optimal parameters of a spline-based empirical potential combining Stillinger-Weber and modified embeddedatom forms are determined. Accuracy of the potential is demonstrated by calculations of ideal shear, stacking fault, vacancy migration, elastic constants and phonons all between 0 and 100 GPa. Consistency with existing models and experiments is demonstrated by predictions of screw dislocation core structure and deformation twinning in a tungsten nanorod. Lastly, the potential is used to study the stabilization of fcc tungsten at high pressure.

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 titaniumniobium 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.