Microstructural characterization of α2 + B2 titanium aluminide intermetallic (Super-α2) using transmission electron microscopy

Dislocation structures in as-received and plastically deformed commercial α 2 + B2 and homogeneous ordered B2 intermetallic titanium aluminide alloys (“super-α2”) were characterized with transmission electron microscopy. Thin foils prepared by twin-jet electropolishing and ion beam thinning were found to yield different deformation structures. Electropolished foils were found to contain lath-like bands of dislocation loops with 1 2 〈111〉 Burgers' vectors (b) in the B2 phase that were actually thinning artifacts. Dislocations in lightly deformed ion-beam-thinned foils appeared to be predominantly screw dislocations with b = 1 2 〈111〉