Embracing the Chaos: Alloying Adds Stochasticity to Twin Embryo Growth

Abstract

High-throughput atomistic simulations reveal the unique effect of solute atoms on twin variant selection in Mg-Al alloys. Twin embryos first undergo a stochastic incubation stage when embryos choose which twin variant to adopt, and then a deterministic growth stage when embryos expand without changing the selected twin variant. An increase in Al composition promotes the stochastic incubation behavior on the atomic level due to nucleation and pinning of interfacial disconnections. At compositions above a critical value, disconnection pinning results in multiple twin variant selection.

Thermodynamically-consistent derivation and computation of twinning and fracture in brittle materials by means of phase-field approaches in the finite element method

“…Under these numerical conditions, a small orientation of the twin evolution is realized due to the difference in the driving force for twinning, which is a factor of (F η ) −1 . We emphasize that the twin morphology at the final stage is in qualitative agreement with the (static) phase-field results [47] and molecular dynamics simulations [121], thus serving to verify the set of results in Fig. 33(a, b)(i, ii) for the proposed time-dependent phase-field model.…”

“…Therefore, understanding and predicting the twinning behavior during plastic deformation of magnesium is critical toward the realization of next-generation lightweight metallic materials for application in automotive and defense industries. In order to investigate twinning in magnesium, various techniques such as high-resolution transmission electron microscopy [118], visco-plastic self-consistent polycrystal models [119], elastoplastic self-consistent polycrystal models [120], molecular dynamics simulations [121], crystal plasticity models [122], and quasi-static phase-field models [47] have been employed. In this paper, the fracture and twinning behaviors of single crystal magnesium are studied using an advanced time-dependent phase-field theory by numerically solving engineering problems.…”

Thermodynamically-consistent derivation and computation of twinning and fracture in brittle materials by means of phase-field approaches in the finite element method

“…Therefore, understanding and predicting the twinning behavior during plastic deformation of magnesium is critical towards the realization of nextgeneration lightweight metallic materials for use in automotive and defense applications. In order to investigate twinning in magnesium, various techniques such as high-resolution transmission electron microscopy (Sim et al, 2018), visco-plastic self-consistent polycrystal models (Lebensohn et al, 1993), elasto-plastic self-consistent polycrystal models (Turner and Tomé, 1994), molecular dynamics simulations (Hu et al, 2020b), crystal plasticity models (Lindroos et al, 2017), and quasi-static phase-field models (Clayton and Knap, 2011) have been employed. In this paper, the fracture and twinning behaviors of single crystal magnesium are studied using an advanced time-dependent phase-field theory by numerically solving engineering problems.…”

Strengthening magnesium by design: integrating alloying and dynamic processing

“…12(a)(b)). Growth parallel to the twin plane, called propagation, is also accommodated by TDs, which form basal-prismatic (BP) interfaces, prismatic-basal (PB) interfaces, and conjugate twin boundaries (Hu et al, 2020a;Ostapovets & Gröger, 2014). During twin propagation, solute atoms are expected to form barriers that resist the propagation of the BP and PB interfaces.…”