DISLOCATION TRANSFORMATIONS AND THE ANOMALIES OF DEFORMATION CHARACTERISTICS IN TIAL .2. THE STRUCTURE OF DISLOCATION ENSEMBLE - EXPERIMENT AND THEORY

Results of an electron microscope investigation of dislocations in TiAl are presented. An analysis made of typical dislocation configurations such as blocked single dislocations and blocked superdislocations-traps for single dislocations. Theoretical models are assigned to the configurations observed. Fundamentals of a phenomenological approach to describe plastic deformation are outlined. This approach enables allowance for dislocation transformations of several types. An analysis of the dislocation transformations is made, with a view to reveal those which may be responsible for the temperature peak of the yield stress. The concepts of the possible structure of the dislocation ensemble in TiAl are formulated.