X-ray topography and crystal orientation study of a nickel-based CMSX-4 superalloy single crystal

A study of the crystal orientation and structural perfection of single crystal blades obtained by Bridgeman method from CMSX-4 nickel superalloy at various withdrawal rates between 1 and 5 mm/min was carried out using the Laue diffraction method and X-ray diffraction topography methods as well as electron scanning microscopy. Blades consisted mainly of the regular gamma' phase, with [001](gamma')-type direction close to the blade axis. The angle of deviation of the [001](gamma') direction in relation to the blade axis changes between the blade locking piece and end. The dependence this angle on the distance from the locking piece has been named as the crystal orientation distribution (COD). It was found that the nature of COD changes with a change in the withdrawal rate. The change in the withdrawal rate also results in a rotation of [001](gamma')-type direction in relation to the blade axis. The best blades in terms of orientation and structural perfection were obtained for the withdrawal rate of 3 mm/min. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim