Reliability Analysis on Errors of Measuring Residual Stress in 7050 Aluminum Alloy with X-Ray Diffraction

The error distribution of residual stress tested by X-ray diffraction on 7050 aluminum alloy was studied. In this paper, residual stress was measured, independently and repeatedly, many times on 7050 aluminum alloy with X-ray diffraction, then the errors about 50 stress values within the range of 30MPa were analyzed by the hypothesis testing. The results indicate that the errors of the residual stress measurement on 7050 aluminum alloy were followed the law of normal distribution about and the errors can be estimated by the least square calculator. The research lays the foundation to subsequent researches on the inherent law of the residual stress measurement with X-ray diffraction and the residual stress distribution and accuracy of stress of material surface.