The effect of precipitate shape and orientation on dispersion strengthening in high strength aluminium alloys

Appropriate versions of the Orowan equation have been developed for aluminium alloys containing rationally oriented {111}(alpha) and {100}(alpha) precipitate plates, and < 100 >(alpha) precipitate rods, and the effects of precipitate shape and orientation on dispersion strengthening have been examined quantitatively. The proposed model appears to give predictions which agree well qualitatively with experimental observations that high tensile strength is frequently associated with alloys containing intrinsically strong, plate-shaped precipitates with rational crystallographic habit planes and large aspect ratios.