An observation on the experimental measurement of dislocation density

TL;DR

This paper critically examines the common neglect of elastic strain gradients in measuring dislocation density, highlighting potential errors and emphasizing the importance of spatial strain variations for accurate estimates.

Contribution

It reveals that ignoring elastic strain gradients can cause significant errors in dislocation density measurements and underscores the need to consider spatial strain variations.

Findings

Neglecting elastic strain gradients leads to substantial measurement errors.

Spatial variations of elastic strain are crucial for accurate dislocation density estimation.

Ignoring strain gradients can compromise the reliability of GND density measurements.

Abstract

The common practice of ignoring the elastic strain gradient in measurements of geometrically necessary dislocation (GND) density is critically examined. It is concluded that the practice may result in substantial errors. Our analysis points to the importance of spatial variations of the elastic strain field in relation to its magnitude in inferring estimates of dislocation density from measurements.