A mean-field interatomic potential for a multi-component β-type titanium alloy

• We propose a simplified mean-field scheme to obtain potentials for complex alloys.
• A potential is constructed for Ti2448 with 4 elements based on experiment and calculations.
• The potential gives stable bcc phase, and E–R relation agrees fairly with Rose’s equations of state.
• Calculated point defect energies and structures show the abnormality of Ti2448.
• The potential can be used to study the peculiar elastic and plastic behavior of Ti2448.

By employing the mean-field concept and the embedded-atom method, an interatomic potential was constructed for a β-type titanium alloy, Ti–24Nb–4Zr–7.9Sn (Ti2448). The alloy was assumed to consist of one single special “element”, and its properties were obtained by averaging the interaction between all elements in the alloy. The lattice parameter, shear modulus, bulk modulus, anisotropy ratio and vacancy formation energy from experiments and the cohesive energy from ab initio calculations were used for fitting the potentials. Verification of the present potential was performed by the calculation of the cohesive energies under various lattice structures, the equation of state and point defect energies. Molecular dynamics simulations showed that the present potential is capable of reproducing various manners of plastic deformation, e.g., dislocation nucleation and propagation, deformation twinning, phase transformation, etc. The results show that for such disordered alloys, while retaining the reliability, the mean-field scheme is much simplified compared with traditional methods of potential construction, hence making it possible to study multi-component engineering alloys, such as Ti2448.

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