A DEFORMATION-BASED MODEL FOR RECRYSTALLIZATION OF ANISOTROPIC MATERIALS

In materials with high plastic anisotropy some orientations deform muc h more than others, leading to a large variation in strain and strain energy. It has been observed in several mineral systems that those ori entations which are most deformed (''soft'') dominate the recrystalliz ation texture. A model is proposed which relies on a self-consistent v iscoplastic theory to predict the deformation of individual grains. Fr om this model the strain energy is determined, assuming a linear harde ning law. Highly strained grains are likely to recrystallize by nuclea tion or to disappear through invasion by neighbors. The recrystallizat ion texture is due to a balance between nucleation (defined by two par ameters, a probability parameter A and a threshold parameter B) and bo undary mobility (described by a parameter C). The texture evolution du ring dynamic and static recrystallization for halite, quartz and ice h as been simulated and results agree surprisingly well with textures ob served in experimentally and naturally deformed, recrystallized materi als which were difficult to explain before. The model is easily incorp orated in polycrystal plasticity codes. (C) 1997 Acta Metallurgica Inc .