Systematic errors in dislocation densities measured by thin film electron microscopy

Abstract
The dislocation density N m measured by the thin film electron microscope technique may be considerably below the true bulk density N. Lower limits ranging from 2ċ4 to 6 have been reported for K=N/N m for heavily deformed Al. Measurements of electrical resistivity, flow stress and N m are used to show that K for Al extended up to 13% has the value unity, compared with 6 for Al compressed 75%.