Observation of dislocation loop arrays in fatigued polycrystalline pure iron

Abstract

Polycrystalline iron (99·98% purity) specimens were fatigued in cyclic strain at room temperature and examined by transmission electron microscopy. Thin foils obtained from regions near the surface of the specimen (<25 microns) showed well-developed arrays of parallel rows of dislocation loops. Similar dislocation arrangement was not observed at the mid-thickness region of the specimens.