Such glide was computer simulated in single crystals which contained spherical precipitates, and the critical resolved shear stress was derived. The simulations were based on the equilibrium of resolved stresses in one glide plane, and the elastic dislocation self-stress was taken into account. The particle-radius distribution was that of an Ostwald-ripened crystal. Particle arrangements were computer-generated in space, with various degrees of randomness in their nearest-neighbor spacings. An experimentally accessible parameter, Z (between 0 and 1), was defined which described this randomness. The computer-generated arrangements were compared with scanning electron and atomic force micrographs of a real specimen. The investigated specimen could be described well by Z = 0.55. The dependence of the critical resolved shear stress upon the particle volume fraction, the mean particle radius and the Z-valus was calculated by simulation. The critical resolved shear stress decreased linearly by 20% in going from uniform particle arrangements (Z = 0) to random ones (Z = 1).

Computer Simulations of Orowan Process Controlled Dislocation Glide in Particle Arrangements of Various Randomness. V.Mohles, B.Fruhstorfer: Acta Materialia, 2002, 50[10], 2503-16