Dislocation structures in Zr3Al-based alloys

Transmission electron microscopy has been used to investigate dislocation structures in deformed binary and ternary Zr3-Al-based alloys. In the binary alloy deformed at temperatures between 293 and 673 K the dislocations in the Zr3Al phase consisted of a/3<112>-type partial dislocations bounding superlattice intrinsic stacking fault on brace111brace planes. The brace111brace a/3<112-bar> stacking fault energy was approximately 2 mJ m-2 at 673 K. In binary specimens deformed between 873 and 1073 K cube slip predominated. Dislocations consisted mainly of a/2 <110> pairs separated by antiphase boundary. For this temperature range the brace100brace a/2<011> antiphase boundary energy was between 30 and 45 mJ m-2. Alloying with niobium or titanium was found to increase the brace111brace a/3<112-bar> stacking fault energy and thus increase the propensity for antiphase boundary-type dissociation. (author)