The relationship between flow stress and dislocation behaviour in [111] aluminium single crystals

Abstract

Abstract Slip bands and the corresponding dislocation structures in [111] aluminium single crystals at various strains have been simultaneously studied in detail by high-voltage electron microscopy to investigate the mean free path of mobile dislocations. The length of the slip bands is determined by the cell size at every strain and decreases with increasing strain as a function of the inverse of strain. It has been also clarified by the in situ deformation technique that the mean free path of mobile dislocations is precisely determined by the cell size. Each mobile dislocation is retarded by the forest dislocations in each cell wall, so that the flow stress necessary for the dislocation motion is determined by the forest cutting process of the dislocations. On the basis of the dislocation behaviour, the relationship between flow stress and cell size has been quantitatively clarified.