The distribution of deformation in lead fatiguedin vacuo

Abstract

Observations have been made on the nature of the deformation, hardening, and recrystallization in polycrystalline specimens of high-purity lead fatigued in reverse-plane bending in vacuo (approx. 5 × 10⁻³ or 2 × 10⁻⁶ min Hg). Fatigue straining induced slip, and grain boundaries to migrate to more stable positions at ± 45 degrees to the principal stress axis. The early distribution of slip-trace angles was in good agreement with the angular distribution which Hedgepeth (1952) predicted on a basis of the maximum shear stress criterion and by neglecting the slip and grain-boundary interaction. Evidence for this latter interaction was found as hard zones up to 100 microns wide near grain boundaries. These zones were the sites for recrystallization and grain growth.