Twin boundary migration mechanisms in quasi-statically compressed and plate-impacted Mg single crystals
Kelvin Y. Xie, Kavan Hazeli, Neha Dixit, Luoning Ma, K.T. Ramesh, Kevin J. Hemker
Abstract
>-axis quasi-statically compressed single crystals are relatively smooth. At these modest stresses and rates, the twin boundaries were found to migrate predominantly via shear (i.e., disconnection nucleation and propagation). By contrast, in the plate-impacted crystals, which are subjected to higher stresses and rates, twin boundary migration was facilitated by local atomic shuffling and rearrangement, resulting in rumpled twin boundaries. This rate dependency also leads to marked variations in twin variant, size, and number density in Mg. Analogous effects are anticipated in other hexagonal closed-packed crystals.
Topics & Concepts
Crystal twinningNucleationMaterials scienceTransmission electron microscopyAtomic unitsCrystallographyCondensed matter physicsGeometryComposite materialChemistryNanotechnologyMicrostructurePhysicsOrganic chemistryMathematicsQuantum mechanicsMagnesium Alloys: Properties and ApplicationsMicrostructure and mechanical propertiesHigh-Velocity Impact and Material Behavior