An Electrical Resistivity Study of Lattice Defects in Deformed Iron

To elucidate the effects of purify and deformation temperature on the production of lattice defects, strain-induced electrical resistivity Δρ has been measured at -196°C as a function of true strain ε_T. In deformation at -196°C, Δρ varying according to ε_T^3/4 has been divided into a part Δρ_a which anneals out at room temperature and its residual part Δρ_r. The latter changes linearly with ε_T. The rate of increase of Δρ becomes larger as the purity is reduced, but does not depend on method of straining, i.e., interrupted deformation or continuous one. In deformation at room temperature, the rate is much lower than that at -196°C, and is less dependent on purity. An analysis of Δρ_r, and Δρ under room temperature deformation indicates that dislocations are the major contributions to Δρ_r and Δρ, and the specific resistivity of dislocations in iron is evaluated as (1.0±0.4)×10^-18 Ω cm³.