X-ray stress analysis on plastically deformed metals

Abstract

Previous hypotheses on the causes of residual lattice strains in plastically deformed polycrystalline metals are reviewed briefly and the validity of x-ray stress measurements in such cases is examined. Experiments designed to investigate the importance of possible contributory processes to the residual lattice strains have been carried out on iron and mild steel. The results are consistent with a combination of macroscopic and pseudo-macroscopic residual stress systems. No evidence has been found for any significant intergranular system of Heyn stresses. Previous explanations have been found to be insufficient to account for all the effects observed and it is suggested that an additional pseudo-macroscopic process is also operative arising from differences in strength between the crystallites and their boundary regions in each deformed grain.