Cyclic deformation of silicon-iron single crystals oriented for single glide

Abstract

Abstract The cyclic deformation behaviour of silicon (3%)-iron single crystals has been investigated as a function of the number of cycles and the cyclic hardening curves have been correlated with the change of dislocation microstructures and surface slip patterns. The hardening curve can be divided into two parts, i.e. the rapid-hardening and the saturation-hardening regions. In the former region, coarse slip bands formed by the first half-cycle become less and less definite with the progress of cycling and eventually disappear. This is found to be attributable to the plastic anisotropy in this system. Within crystals, a bundle structure of dislocations is formed and this is successively transformed into a ragged cell structure. In the saturation-hardening region, a well defined two-dimensional cell structure with highly regular wall arrangements has been developed. The imposed strain is accommodated mainly by screw dislocations travelling to and fro in the regions between walls.