Construction of $n$-body potentials for hcp-bcc metal systems within the framework of embedded atom method

An effective fitting approach together with ab initio calculation is proposed for construction of $n$-body potentials for hcp-bcc metal systems under the framework of the embedded atom method. In two representative systems, i.e., the miscible Co-Nb and immiscible Sc-W systems, the potentials so constructed are proven to be relevant in reproducing some static properties. Moreover, applying the potentials, molecular dynamics simulations using solid solution models predict that the glass-forming ranges of Co-Nb system are within 18–84 at. % of Nb, and reveal that amorphous alloys can be formed with Sc-enriched compositions and the critical solubility of W in the Sc-based solid solution is 15 at. %. Interestingly, the predicted composition ranges favoring metallic glass formation are in good agreement with the experimental observations.

Figure 1

The projections of atomic positions of (a) ${\mathrm{Co}}_{90}{\mathrm{Nb}}_{10}$, and (b) ${\mathrm{Co}}_{80}{\mathrm{Nb}}_{20}$ hcp-solid solution models, respectively, after annealing at 300 K for 2 ns. Open circles: Co. Filled triangles: Nb.

Figure 2

The projections of atomic positions of (a) ${\mathrm{Co}}_{10}{\mathrm{Nb}}_{90}$, and (b) ${\mathrm{Co}}_{20}{\mathrm{Nb}}_{80}$ bcc-solid solution models, respectively, after annealing at 300 K for 2 ns. Open circles: Co. Filled triangles: Nb.

Figure 3

For the Co-Nb system, the calculated total pair correlation functions of the solid solution models upon annealing at 300 K for 2 ns. (Note: the left five lines are for the hcp solid solution models and the right five lines are for the bcc solid solution models.)

Figure 4

The projections of atomic positions of (a) ${\mathrm{Sc}}_{90}{\mathrm{W}}_{10}$, and (b) ${\mathrm{Sc}}_{80}{\mathrm{W}}_{20}$ solid solution models, respectively, after annealing at 300 K for 2 ns. Open circles: Sc. Filled triangles: W.

Figure 5

For the Sc-W system, the calculated total pair correlation functions of the solid solution models upon annealing at 300 K for 2 ns. (Note: the left five lines are for the hcp solid solution models and the right five lines are for the bcc solid solution models.)