Coupling strengthening mechanism of precipitate and solute atoms in edge dislocation motion of Al-Mg-Si alloy

Abstract

To investigate the coupling strengthening mechanism of precipitate and Cu solute atoms in Al-Mg-Si alloy, the molecular dynamics model of edge dislocation motion interacted with precipitate and Cu solute atoms was established. The dislocation length is increased in the dislocation-precipitate interaction due to the bending and bowing of the edge dislocation around the precipitate. No coupling between precipitate and solute can be found in material strengthening in cases with lower solute concentrations. The exponential effect of the coupling effects between precipitate and solute on material strengthening is found when the solute concentration is increased above 0.3.at% at room temperature. The change of the edge dislocation caused by solute atoms around the precipitate is the key reason for the strengthening coupling effect. Furthermore, the effects of temperature variations on the coupling effect are more pronounced than the effects of shear strain rate variations. When the temperature is increased from 200K to 500K, the critical ratio of solute and precipitate strengthening is decreased from 1.5 to 0.4.