Interaction Between Basal Slip and a Mg17Al12 Precipitate in Magnesium

We performed molecular dynamics simulations and investigated interactions between a Mg₁₇Al₁₂ precipitate and a basal dislocation in magnesium. Modified embedded-atom method potentials for multiple-component systems were used in our simulations. The simulation results show that the basal dislocation is able to shear through the matrix and the precipitate/matrix interface, without creating a loop around the precipitate. The precipitate is only elastically deformed by the external shear strain. This interaction can be considered an extreme case of the Orowan mechanism when the strength of the precipitate/matrix interface is weak. Cross slip of the basal dislocation was observed when the precipitate size was 3.0 nm. The dislocation changed its slip plane to another basal plane via the \( (01\overline{1} 0) \) prismatic and the \( (0\overline{1} 11) \) pyramidal planes, creating jogs on these non-basal planes. The jogs had low mobility and debris was created when the jogs were dragged forward by the Shockley partial dislocations.