The use of oscillation on PSD-based instruments for X-ray measurement of residual stress

Abstract

Measurements of surface residual stress by X-ray diffraction can be accomplished very rapidly using a position-sensitive detector (PSD) to record the diffraction profile. It is shown that when the sample and detector are fixed during data accumulation, the profile shape may be distorted by large grain size or preferred orientation, which results in substantial error in the calculation of residual stress. Sample oscillation decreases the sensitivity of the PSD system to such microstructural variables in many cases. Instruments employing a PSD to measure surface residual stress should be designed with the capability of oscillating either the sample or the measuring head (X-ray tube and detector).