A low-temperature prismatic slip instability in Mg understood using machine learning potentials

Liu, Xin; Niazi, Masoud Rahbar; Liu, Tao; Yin, Binglun

doi:10.1016/j.actamat.2022.118490

Cited by 7 publications

(1 citation statement)

References 31 publications

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“…To begin an investigation of this issue, we have performed first-principles calculations of the interaction energy of Zn with the prism screw core; DFT details are the same as those used for the edge core. The prism screw core is unstable in pure Mg [32] and so we stabilize this core by placing a Zn solute at the center of the core (position just below the S in figure 10). We then measure the Zn/screw interaction at all other locations around the core with the central Zn atom remaining in the system.…”

Section: Discussionmentioning

confidence: 99%

Strengthening of edge prism dislocations in Mg–Zn by cross-core diffusion

Niazi,

Curtin

2024

Modelling Simul. Mater. Sci. Eng.

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The activation of prismatic slip in Mg and its alloys can be beneficial for deformation and forming. Experiments show that addition of Zn and Al solutes have a softening effect at/below room temperature, attributed to solutes facilitating basal-prism-basal cross-slip of prismatic screw dislocations, but a strengthening effect with increasing temperature. Here, the dynamic strain aging mechanism of cross-core diffusion within the prismatic edge dislocation is investigated as a possible mechanism for the strengthening at higher temperatures. First-principles calculations provide the required information on solute/dislocation interaction energies and vacancy-mediated solute migration barriers for Zn solutes around the dislocation core. Results for Mg-0.0045Zn show that cross-core diffusion notably increases the stress for prismatic edge dislocation glide but that the strengthening remains roughly 30% of the experimental strength. Other possible strengthening mechanisms of (i) solute drag of the prism edge dislocation and (ii) solute interactions and/or diffusion within the prismatic screw core, are then briefly discussed with some quantitative assessments pointing toward areas for future study.

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Section: Discussionmentioning

confidence: 99%