Abstract
The deformation behaviour of two-phase (γ + α2) titanium aluminide was investigated by high-resolution transmission electron microscopy. Specimens were deformed in compression at room temperature well beyond the yield point. The α2-Ti3Al lamellae within the γ-TiAl matrix were observed to deform by shearing when intersected by twins. In addition to dislocation slip, plastic deformation in γ-TiAl was found to proceed by (a/6)2 interface. These observations and deformation mechanisms are discussed in terms of the structure of γ-α2 and twin interfaces.