Non-destructive measurement of residual stress by neutron diffraction

Residual stresses can be introduced into components during manufacture and use. They can have a significant influence on the load-carrying capacity and resistance to fracture of these components. It is important that their magnitude and distribution are known accurately for performance to be estimated. In this paper, the neutron diffraction method of measuring these stresses is presented. Procedures are described for achieving accurate and reliable results. It is demonstrated that strains can be determined to a resolution of 10−4, corresponding to a stress of ±7–20 MPa in most engineering materials. Some examples of the application of the technique are considered.