Precipitate sheared by low-angle grain boundary in Mg-Al alloys

The interaction between Mg17Al12 precipitate and low-angle grain boundaries (LAGBs) in Mg-Al alloys was studied using molecular dynamics (MD) simulations. The precipitate was observed to be not sheared by the LAGBs with a small rotation angle < 8 degrees, but sheared by the LAGBs with a large rotation angle >= 9 degrees To explain these two different interaction styles, a critical GB shear was proposed analytically using the Eshelby theory, which indicates that the critical GB rotation angle is 8.4 degrees and agrees well with the current MD simulations. The critical GB shear was found to be related to the aspect ratio of precipitate.

Automated summary

The interaction between Mg17Al12 precipitate and low-angle grain boundaries in Mg-Al alloys was investigated using molecular dynamics simulations. The precipitate was found to be sheared by grain boundaries with a rotation angle of 9 degrees or larger, but not sheared with a rotation angle smaller than 8 degrees. An analytical model based on Eshelby theory was proposed to explain this behavior, and it showed good agreement with the simulation results. The critical shear of the grain boundary was found to be related to the aspect ratio of the precipitate.