Neutron diffraction strain tomography: 2D axisymmetric sample geometry

TL;DR

This paper introduces a neutron diffraction strain tomography method for 2D axisymmetric samples, combining transmission and diffraction features to reconstruct stress fields with comparable accuracy to traditional techniques.

Contribution

The paper presents a novel neutron diffraction tomography approach that reconstructs stress fields from diffracted beam measurements in 2D axisymmetric samples, validated against traditional methods.

Findings

Achieved similar strain accuracy as traditional neutron stress scanning.

Demonstrated feasibility of neutron diffraction tomography for 2D axisymmetric samples.

Discussed practical and theoretical challenges of the new technique.

Abstract

We consider a method for neutron residual strain/stress analysis combining features of transmission strain tomography (e.g. through Braggs edge imaging) and neutron diffraction techniques. Analogous to transmission strain tomography, our approach observes integrals of strain along the path of a beam, however, rather than transmitted beams, we observe a diffracted beam. The practical feasibility of neutron diffraction tomography is demonstrated in case of a 2D axisymmetric sample where the reconstruction of the stress field is determined from the measurement of a strain profile. The reconstruction is compared to a set of measurements made using a traditional neutron stress scanning technique in order to validate the new method. Similar strain accuracy was achieved by the new technique within a reasonable measurement time. The practical and theoretical challenges regarding the technique are also discussed.