Influence of notch geometry and temperature on the mechanical properties of Al‐Mg alloy using molecular dynamics simulations

Abstract

At the near‐threshold regime, small irregularities on the surface can interact with the microstructure and affect the nucleation and propagation of cracks. Molecular dynamics is an effective methodology to investigate the damage evolution at this scale, and three types of defects, namely, triangular, rectangular, and crack, are examined. The effects at different temperatures (10, 300, and 450 K) and depths (2, 4, and 8 nm) are investigated in an aluminum alloy containing 5% magnesium. Cracks propagate via amorphization of the crack tip and, at low temperatures, also through the formation of voids. Elevated temperatures and deeper pits reduce the mechanical strength of the materials, increasing the radius of amorphization, while the effect of the shape on the mechanical properties is negligible. The observed behavior follows a trend observed experimentally and through finite element modelling in the literature, extending the results from the macroscale to the microscale.