In aeroengines or industrial gas turbine blades, it is important to estimate the residual stresses at the surface of the blade root to ensure the structural integrity of the part. Most turbine blades are investment cast superalloys and it is difficult to apply the standard X-ray diffraction method to measure the residual stresses, because of the presence of a coarse grain size in these parts. Therefore a special technique was adopted to enable an estimate of the residual stresses at the surface of the turbine blade dovetail, which is a typical feature of the blade root. This method consists of a combination of the curvature method and the FE analysis. After obtaining a good agreement between the results using this method with the standard X-ray diffraction method in wrought Alloy 718 that possesses a very fine grain size, the residual stress distributions in the subsurface region of cast turbine blade dovetails were successfully obtained.
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