The polygonized sub-grain structure of a plastically deformed metal was treated as an heterogeneous dislocation structure in terms of a composite model, and the relationship of the mean sub-grain size to the total dislocation density and to the applied stress was investigated. The analysis indicated a proportionality between the sub-grain size, d, and the applied stress, σ, of the form, d = KGb/σ; where K was a constant, G was the shear modulus and b was the magnitude of the Burgers vector. This suggested an explanation of the highly disperse values of K, among various materials, as being the result of the influence of several parameters. The proportionality factor between d and ρ-½, where ρ was the total dislocation density, depended upon the volume fraction of hard regions. Account was taken of the fact that sub-structures having the same sub-grain size could store differing dislocation densities.

Subgrain Size in View of the Composite Model of Dislocation Structure. A.Orlová: Materials Science and Engineering A, 2001, 297[1-2], 281-5