Cyclic deformation of silicon single crystals: correlation between dislocation microstructure and mechanical behaviour during linear hardening

A model is proposed to describe cyclic deformation of Si single crystals during the stage of linear hardening observed before stress saturation. The model starts from a wall and channel microstructure of given period, assuming that plastic strain is carried by screw dislocations moving in channels. Internal stresses and dislocation mobility are taken into account. Annihilation of screw segments by cross-slip is compensated by production of new ones from edges bulging out of the walls. Assuming a reasonable distribution of edge dislocation segments, the model satisfactorily describes the shape of stress-strain cycles when walls thicken.