Multislice image simulations of sheared needle‐like precipitates in an Al‐Mg‐Si alloy

The image contrast of sheared needle‐like precipitates in the Al‐Mg‐Si alloy system is investigated with respect to shear‐plane positions, the number of shear‐planes, and the active matrix slip systems through multislice transmission electron microscopy image simulations and the frozen phonon approximation. It is found that annular dark field scanning transmission electron microscopy (ADF STEM) images are mostly affected by shear‐planes within a distance ∼6–18 unit cells from the specimen surface, whereas about 5–10 equidistant shear‐planes are required to produce clear differences in HRTEM images. The contrast of the images is affected by the Burgers vector of the slip, but not the slip plane. The simulation results are discussed and compared to experimental data.