Magnetic studies of the dislocation structure of iron single crystals deformed at 195K and 77K

Abstract

Measurements of the coercive field, the initial susceptibility and the reversible susceptibility in the approach to ferromagnetic saturation show that during low-temperature deformation of iron single crystals mainly screw dislocations are created. Long-range internal stresses are found to be significantly smaller than in crystals deformed at room temperature. Macroscopic slip occurs on several slip systems. In the parabolic region of the work-hardening curves at 195 K the relation$\tau \sim \sqrt N$ is valid, where τ isthe shear stress andN is the dislocation density. In the region of saturation of the shear stress the dislocation density further increases. After room-temperature prestrain the relation$\tau \sim \sqrt N$ appears to hold for 77K-deformation also. Exhaustion hardening of edge dislocation is found at the beginning of the low-temperature deformation.