Dislocation density-based modeling of deformation behavior of aluminium under equal channel angular pressing

Grain size distribution and heat conductivity of copper processed by equal channel angular pressing

“…if the grain volume is used instead of the linear size parameter s. Such simulation has been performed and the matching of the GSDF led to much less accord with the experimental data; namely, the function obtained failed to predict the character of GSDF behavior in the region of small grain sizes. This observation seems [4][5][6][7][8][9][10][11][12][13][14][15][16][17] to support the proposition that the division and conglomeration processes may be considered as essentially one-dimensional ones.…”

“…Fitting parameters of the GSDF curves computed from the experimental data ( Fig. 1) with the help of Equations (15) and (16 The fit with the experimental plots is fairly good, despite crude approximations used in deriving Equation (14). Distribution function (14) is not lognormal, contrary to statements in [1,2,5].…”

“…As a result, a cellular dislocation structure develops with the cell (grain) walls containing a major portion of the dislocation density, as opposed to the cell interior where the dislocation density is significantly lower. Several mechanisms of formation, motion and annihilation of the dislocations within the cell interior and cell walls are known [16,17], which together govern the emerging GSDF and its evolution with the imposed strain. In what follows, we shall not distinguish between the dislocation cells/subgrains and grains, the former being treated as the smallest structural unit.…”

“…In what follows, we shall not distinguish between the dislocation cells/subgrains and grains, the former being treated as the smallest structural unit. As the average dislocation cell/subgrain size scales with the inverse of the square root of the total dislocation density ρ t [16,17], the increase of ρ t with strain promotes grain refinement during straining. We shall also assume that concurrent in situ cell/subgrain growth acts against this trend.…”

“…Specific mechanisms governing the evolution of the dislocation density in cell interiors, c , and in cell walls w , include (i) generation of dislocations due to activation of Frank-Read sources at the cell walls (ii) the motion (transport) of cellinterior dislocations and their 'entrapping' in the walls, and (iii) annihilation due to cross-slip or climb [16,17]. The rate of accumulation of cell interior dislocations is considered to be inversely proportional to their mean free path, which is proportional to the average grain size s m .…”