Mechanical properties of nanocrystalline aluminium: a molecular dynamics investigation

Uniaxial deformation was performed using molecular dynamics to estimate the mechanical properties of nanocrystalline aluminium. It was observed that the stacking faults and sliding of the grain boundaries affected the mechanical properties. In addition, accumulation of atoms near grain boundaries during deformation hardened the nanocrystalline material as the grain diameter increased (reverse Hall-Petch relation). Further, the effects of strain rate and temperature were investigated with various mean grain diameters. Investigation showed that mechanical properties were independent of tested strain rates (10(9)-10(10) s(-1)) and that the nanocrystalline material softened with increasing temperature. The elastic modulus was then compared to experimental results from literature at room temperature. The change in crystalline structure was observed with respect to percent strain and various mean grain diameters of nanocrystalline aluminium. It was observed that stacking faults increased with decreased mean grain diameter, which led to reduced mechanical properties.