Length of dislocations during band formation of irregular plastic flow

Abstract

Average dislocation length during the fast regime (formation and development phase) of deformation bands in aluminum alloy AA 3204 undergoing irregular plastic flow was estimated. It has already been demonstrated that the electrons embedded in dislocation core domains (bound states) in slip planes during the regime expose out to specimen surface and create an extra potential. Hence, the potential at a fixed location was monitored in an electrochemical cell containing a dilute electrolyte. From the measured potential the number of the bound states was calculated and an estimation for total number of dislocated atoms considering probable single and double charge states was carried out. Then, using the data in the literature on number of dislocation events per band taken by acoustic emission technique, the average dislocation length during the fast regime was calculated. For probable charge states such as doublets and singlets, the dislocation lengths were respectively found to be 190 nm and 380 nm for the fast regime. Dislocations of such length were thought to be critical for band formation events of an irregular plastic deformation.