An in-situ study of ordinary dislocation glide in γ-TiAl alloys

Abstract

The glide of ordinary dislocations in the γ phase of TiAl alloys at room temperature is studied by transmission electron microscopy in-situ straining experiments. The dislocations are elongated along their screw direction and anchored at many pinning points which are considered as extrinsic to the dislocations. The dislocation glide is analysed in detail with special attention to the unpinning process. The strength of these extrinsic obstacles is calculated from an analysis of the critical configuration at which they break. The results are discussed with the aim of balancing the contributions of the frictional force and of the strength of the pinning points.