SUBSTRUCTURE FORMATION DURING PLASTIC-DEFORMATION

This work addresses cell formation from an initially homogeneous distr ibution of parallel edge dislocations. We consider an array of interac ting, nearly parallel edge dislocations that glide on a single plane, but may also climb. We obtain a set of nonlinear differential equation s that describe the evolution of the dislocation distribution, and fin d the instability conditions that lead toward cells. Three particularl y interesting results emerge. First, the distribution of edge dislocat ions is always at least mathematically unstable with respect to cell f ormation when dislocations can be created or destroyed. Second, the lo cus of that instability is very sensitive to the efficiency of the dis location creation mechanisms. Third, both relatively equiaxed and high ly elongated cells may form, depending on the temperature and the rati o of the stresses that drive glide and climb.