High-temperature Dislocation-precipitate Interactions in Al Alloys: An in situ Transmission Electron Microscopy Deformation Study

Abstract

The fundamental processes controlling the high-temperature interaction of dislocations with precipitates in Al-alloys were investigated in real time by deforming specimens in situ in the transmission electron microscope at elevated temperature. The observations support a bypass mechanism involving the interaction of lattice dislocations with the precipitate–matrix interface dislocations, where the rate-limiting step in the interaction is the release of the dislocation from the particle. These observations are discussed in relation to high-temperature deformation processes and models.