A novel electronic structure-based prediction of interstitial strengthening in <i>α</i> -titanium

The role of interstitial atoms in tailoring the mechanical properties of titanium (Ti) remains a critical area of research. Using first-principles density functional theory (DFT), the present investigation systematically investigates the influence of interstitial H, C, N, and O on the mechanical behavior of α-Ti. We uncover the correlation between mechanical properties and electronic structure, showing how the elastoplastic properties can be explained using the electronic density of states and charge density analysis. While C, N, and O enhance strength by increasing lattice resistance to plastic deformation, H contributes to softening. Conventional descriptors fail to reliably predict the strengthening effects of interstitial additions. To address this limitation, we introduce Φeff, a novel parameter that quantitatively links yield strength to electronic structure-based descriptors. Derived exclusively from integrated crystal orbital Hamilton population (ICOHP) values, Φeff captures both the impact of interstitial atoms on strengthening and the concentration-dependent evolution of yield strength. By establishing a direct, first-principles-based correlation between interstitial concentration and mechanical performance, this parameter eliminates the reliance on empirical fitting or computationally expensive simulations for quantitatively predicting mechanical properties.