Abstract
In this study, molecular dynamics simulations were performed to study the uniaxial compression deformation of bi-crystal magnesium nanopillars with a twin boundary (TB). The generation and evolution process of internal defects of magnesium nanopillars were analyzed in detail. Simulation results showed that the initial deformation mechanism was mainly caused by the migration of the twin boundary, and the transformation of TB into (basal/prismatic) B/P interface was observed. After that, basal slip as well as pyramidal slip nucleated during the plastic deformation process. Moreover, a competition mechanism between twin boundary migration and basal slip was found. Basal slip can inhibit the migration of the twin boundary, and twins appear at a certain high strain level ( = 0.104). In addition, Schmid factor (SF) analysis was conducted to understand the activations of deformation modes.
Highlights
Magnesium (Mg) alloys have attracted extensive attention due to their exceptional and unique properties, such as low density, high strength, superior damping capacity, and efficient recyclability [1,2,3,4]
By studying the nanopillars with different cross sections shapes and sizes, we found that they have similar deformation mechanism
Subsequently,strain the stress dropped this indicated that plastic deformation began
Summary
Magnesium (Mg) alloys have attracted extensive attention due to their exceptional and unique properties, such as low density, high strength, superior damping capacity, and efficient recyclability [1,2,3,4]. The deformation behaviors of hexagonal-close-packed (hcp) metal involved numerous twinning activities due to their insufficient slip systems [5,6]. Several types of twins have been reported for Mg alloys, including {1011}h1012i, {1012}h1011i, {1013}h3032i,. It is commonly recognized that the {1012} twin is the most common type in hcp metals [9,10,11], which play an important role in the deformation mechanisms of hcp metals [12,13,14]. Twin nucleation and twin growth mechanism has been theoretically studied in hcp metals [15,16,17,18,19,20,21,22].
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