An electrical resistivity study of deformation and recovery of iron at low temperature

Abstract

Wires of three high-purity irons were strained in tension at 77°K while resistivity changes were measured. The resistivity increases linearly with strain for strains up to 17%, although a transient higher rate is observed on initial loading and upon reloading after a momentary interruption or after room temperature recovery. Pulse annealing at temperatures between 77 and 773°K results in a continuous reduction of the strain-induced resistivity with no sharp stages attributable to the annealing out of point defects. There is evidence, however, that dislocation relaxation contributes to the recovery of resistivity even at temperatures as low as 85°K. The resistivity per unit density of dislocation in alpha iron is of the order of 1 × 10⁻¹⁸ ohm cm³.