Comparison of Residual Stress Measurements Using Neutron and X-ray Diffraction around Cold Expanded Holes

Comparative stress measurements using neutron and X-ray data from an FTI 4% cold expanded hole in 7050 T76 aluminium alloy plate are presented. Good agreement is found between neutron and X-ray diffraction results. In combination, these results can be used to follow the effects of a −30kN under-load on the stress field around a cold expanded hole. This underload increases the depth of the compressive layer adjacent to the bore of the hole but reduces the value of the peak compressive stress.