Atomic force microscopy of slip lines on the surface of a fatigued nickel single crystal

Abstract

Atomic force microscopy (AFM) was used to determine the width and the height of slip steps which emerged at the polished surface of a cyclically strained nickel crystal due to strain localization in slip bands (SBs), after a deformation of one half-cycle in tension. In addition to the AFM measurements the dislocation arrangements beneath the specimen surface were imaged with scanning electron microscopy (SEM), applying the electron channelling contrast technique. The evaluation of the AFM and SEM measurements made it possible to determine the volume fraction of slip bands and the spectrum of resolved shear strains in the SBs for the imposed shear strain amplitude. The results are discussed within the framework of the 'two-phase' model of Winter.