The mechanical properties of metallic materials are intrinsically linked to their microstructure and lattice defect densities. This study investigates the kinetics of lattice defects - specifically the introduction, migration, and annihilation of vacancies and dislocations - during the tensile deformation of pure Fe. We employed a pseudo-in situ electrical resistivity measurement technique, overcoming the challenge of measuring specimen dimensions during deformation by applying Matthiessen's empirical relationship. A precise linear correlation was established between resistivity at 77 K and the resistance ratio (R = ρ S300 /ρ S77), which allowed for the estimation of resistivity changes without geometric data. Experimental results revealed that the resistivity component associated with vacancies increased linearly with applied strain, notably even within the elastic deformation region. Post-yield, the resistivity attributed to dislocations increased drastically, indicating significant dislocation multiplication. By analysing resistance relaxation during unloading and stagnation at 273 K, we successfully deconvoluted the total resistivity increase into vacancy-derived and dislocation-derived components. This analysis suggests vacancies are generated via dislocation intersections during both deformation and elastic recovery. This bulk-sensitive method complements transmission electron microscopy by providing intrinsic defect information free from thin-foil surface effects.
Ueda et al. (Thu,) studied this question.