Fracture behaviour of Ti3Al single crystals for the basal slip orientation

Results on optical microscopy, scanning electron microscopy and transmission electron microscopy are presented for a compression deformed single crystal Ti3Al (D019 structure) with an orientation where basal slip is operative. It was found that short bands of {11̄00} prism slip form accompanying the (0001) basal slip. The macrocleavage surface consists of microcracks of shear type along the (0001) basal slip planes and decohesion in the {12̄10} prism planes. A model for shear microcrack nucleation with screw a-superdislocations interacting in the slip band of the basal planes was suggested. The macrocracks path behaviour in Ti3Al single crystal is discussed on the basis of the model proposed.