Tensile Mechanical Performance of Horizontally Twinned Al Nanopillar by Molecular Dynamics Analysis.

Twin boundaries are known for their strengthening influence and elevation of ductility in metallic nanopillars. They function both as a source of dislocation nucleation and as impediments to dislocation mobility. This study employs molecular dynamics simulations to examine the tensile properties, specifically strength, and ductility, of a twinned Al nanopillar featuring a horizontally orientated [111] twin boundary subjected to uniaxial tensile loading. Five models were constructed using Atomsk by varying the number of twin boundaries ranging from 1 up to 7, and an additional Al sample free of twins was also created to compare the changes in twin boundaries. The tensile deformation was performed at room temperature using a constant strain rate of 10^10 s^(-1) for 30 ps. The results indicate that the twinned nanopillars exhibit greater peak strength than the single-crystalline Al model of similar size, suggesting that the ultimate tensile strength is significantly impacted by an increase in the number of twin boundaries. The findings indicated that reduced intertwin spacing resulted in reduced yield strength, elucidating the anomalous Hall-Petch relationship. The post-processing of the simulation data was conducted by dislocation extraction analysis (DXA) provided by OVITO. This study explored variations of deformation mechanisms in relation to varying twin spacings by analyzing defect quantities and dislocation density evolution. This research offers significant insights for the advancement of high-performance ductile aluminum.

Recommended citation: Hasan, M. S. & Joti, Z. S. (2024). "Tensile Mechanical Performance of Horizontally Twinned Al Nanopillar by Molecular Dynamics Analysis." Proceedings of the 8th International Conference on Mechanical, Industrial and Energy Engineering. Khulna, Bangladesh.