Energetic Origins of Competing Deformation Modes in Metastable Titanium Alloys

Fuente: arXiv
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Main Authors: Chen, Ganlin, Pillai, Deepak V, Zheng, Yufeng, Qi, Liang
Format: Preprint
Published: 2025
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author Chen, Ganlin
Pillai, Deepak V
Zheng, Yufeng
Qi, Liang
author_facet Chen, Ganlin
Pillai, Deepak V
Zheng, Yufeng
Qi, Liang
contents Metastable alloys, such as $β$-phase titanium (Ti) alloys with a body-centered cubic (BCC) lattice, can exhibit exceptional mechanical properties through the interplay of multiple deformation mechanisms -- diffusionless phase transformations, deformation twinning, and conventional dislocation slip. However, understanding how these mechanisms compete or cooperate across a wide range of metastable alloys and loading conditions remains a fundamental challenge. Here, we employ molecular dynamics (MD) simulations to investigate the nucleation behavior of competing deformation modes in metastable $β$-Ti alloys as a function of temperature, composition, and loading conditions. We reveal that twinning pathways emerge through reversible transformations between the $β$ phase and the orthorhombic $α"$ phase, in agreement with crystallographic theories. Quantitative analyses demonstrate that the dominant deformation mechanisms and preferred twinning-plane orientations are governed by two key energetic parameters: the free energy barrier for homogeneous $β\leftrightarrow α"$ transformations and the misfit strain energy along specific phase boundaries. These energetic quantities vary systematically with thermodynamic and mechanical conditions, thereby rationalizing the deformation mode transitions observed in both simulations and experiments. These energetic metrics offer a physically grounded and computationally tractable basis for designing next-generation metastable alloys.
format Preprint
id arxiv_https___arxiv_org_abs_2510_13113
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Energetic Origins of Competing Deformation Modes in Metastable Titanium Alloys
Chen, Ganlin
Pillai, Deepak V
Zheng, Yufeng
Qi, Liang
Materials Science
Metastable alloys, such as $β$-phase titanium (Ti) alloys with a body-centered cubic (BCC) lattice, can exhibit exceptional mechanical properties through the interplay of multiple deformation mechanisms -- diffusionless phase transformations, deformation twinning, and conventional dislocation slip. However, understanding how these mechanisms compete or cooperate across a wide range of metastable alloys and loading conditions remains a fundamental challenge. Here, we employ molecular dynamics (MD) simulations to investigate the nucleation behavior of competing deformation modes in metastable $β$-Ti alloys as a function of temperature, composition, and loading conditions. We reveal that twinning pathways emerge through reversible transformations between the $β$ phase and the orthorhombic $α"$ phase, in agreement with crystallographic theories. Quantitative analyses demonstrate that the dominant deformation mechanisms and preferred twinning-plane orientations are governed by two key energetic parameters: the free energy barrier for homogeneous $β\leftrightarrow α"$ transformations and the misfit strain energy along specific phase boundaries. These energetic quantities vary systematically with thermodynamic and mechanical conditions, thereby rationalizing the deformation mode transitions observed in both simulations and experiments. These energetic metrics offer a physically grounded and computationally tractable basis for designing next-generation metastable alloys.
title Energetic Origins of Competing Deformation Modes in Metastable Titanium Alloys
topic Materials Science
url https://arxiv.org/abs/2510.13113