Accuracy and stability of 2D-XRD for residual stress measurement

Stress measurement with two-dimensional X-ray diffraction is based on the direct relationship between the stress tensor and diffraction cone distortion. Since more data points at more orientations are used for stress calculation, 2D-XRD can measure stress with high sensitivity, high speed and high accuracy. It is especially suitable for samples with large crystals, textures and curved surface. Ten almen strips were used for Gage R&R test of a 2D-XRD system for stress measurement in 1998. Since then there have been many advances in two-dimensional X-ray diffractometer, including detector technology, X-ray source and optics, goniometer, and data evaluation software. This paper covers accuracy and stability of stress measurement on the same almen strips with a 2D-XRD system. (author)