NEUTRON DIFFRACTION MEASUREMENT OF RESIDUAL STRESS FIELDS—THE ANSWER TO THE ENGINEERS’ PRAYER?

Abstract Design and Production Engineers wish to know the magnitude of residual stresses throughout their fabricated components and weldments in order that they can estimate their maximum loading and fatigue life. A small meter placed on the surface of the component, on which one simply dials a position in the sample and the size of the sampling volume and obtains a read-out of the absolute magnitude and direction of the stress averaged over the volume, would do nicely! At the present time neutron diffraction comes closest to this ideal, but falls far short of it. The technique of stress measurement using neutron diffraction is discussed, with its advantages and outstanding problems, and its use in a number of practical cases is described. KEY WORDS: Neutron diffractionresidual stressfatigue lifeclastic constantsweldments