A method to measure the dislocation link length distribution in dislocation structures

Abstract

A method to measure the dislocation link length distribution in a network-like dislocation structure has been developed. It is based on the rapid and automatic recording of cumulative chord length distributions from electron transmission micrographs of the structures using a quantitative television microscope (QTM). In a first step, this distribution is converted to the true planar link distribution which exists in the micrograph. In a second step, this is then transformed to the three-dimensional link distribution. The validity of the conversion has been checked and found quite satisfactory by applying the method to a network model constructed with a known link distribution. Finally an example is shown of evaluations of dislocation distributions for dislocation structures developed during creep and recovery in a 20% Cr-35% Ni-steel.