Interatomic potential for the NiTi alloy and its application

• A new potential for the NiTi alloy is constructed.
• Lattice properties and elastic behaviors for both B2 and B19′ phases are correctly predicted.
• Temperature-driven phase transformation agrees with the experiments.
• Superelastic behavior is captured.

We construct a new interatomic potential for the NiTi alloy, consisting of the previously existing potentials for Ni and Ti and the cross-interaction terms by fitting to ab initio or experimental data of several Ni–Ti compounds. This potential correctly reproduces the lattice parameter, cohesive energy and equation of state for B2, B19 and B19′ phases. It also predicts three elastic constants of B2 (austenite) phase matching with experiments and thirteen elastic constants of B19′ (martensite) phase in satisfactory agreement with ab initio calculations, which are provided for the first time in comparison with other developed potentials. Additionally, the calculated moduli for B2 and B19′ are in accurate accord with the experimental findings. These good consistencies validate the usefulness of this potential for modeling the martensitic transformation of NiTi alloy induced by temperature or stress control.

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