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arXiv · 2504.18378

Ab initio modeling of TWIP and TRIP effects in $\beta$-Ti alloys

David Holec·Johann Grillitsch·Jose L. Neves·David Obersteiner·Thomas Klein
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Abstract

Transformations in bcc-$\beta$, hcp-$\alpha$, and the $\omega$ phases of Ti alloys are studied using Density Functional Theory for pure Ti and Ti alloyed with Al, Si, V, Cr, Fe, Cu, Nb, Mo, and Sn. The $\beta$-stabilization caused by alloying Si, Fe, Cr, and Mo was observed, but the most stable phase appears between the $\beta$ and the $\alpha$ phases, corresponding to the martensitic $\alpha''$ phase. Next, the $\{112\}\langle11\bar1\rangle$ bcc twins are separated by a positive barrier, which further increases by alloying w.r.t. pure Ti. The $\{332\}\langle11\bar3\rangle$ twinning yields negative barriers for all species but Mo and Fe. This is because the transition state is structurally similar to the $\alpha$ phase, which is preferred over the $\beta$ phase for the majority of alloying elements. Lastly, the impact of alloying on twin boundary energies is discussed. These results may serve as design guidelines for novel Ti-based alloys with specific application areas.

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David Holec, Johann Grillitsch, Jose L. Neves, David Obersteiner, Thomas Klein. 2025-04-25. Ab initio modeling of TWIP and TRIP effects in $\beta$-Ti alloys. https://doi.org/10.1557/s43578-025-01657-w

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