Effect of stress gradients in the surface layer of beryllium on X-ray stress measurement

The effects of stress gradients in beryllium surface layers on traditional X-ray stress measurements are investigated by relationship analysis of d vs. (sin ψ)2 plots with stress gradient in the surface layers of beryllium. The results show that over the range of (sin ψ)2≤0.5, there are significant effects of stress gradient on the measurement results. The stress measurement error resulting from the stress gradient is decreased using a vanadium target and high ψ range.