On the relationship between texture characteristics and residual stress levels: An X-ray diffraction study on α-Al2O3 hard coatings

Abstract

[0 0 l] textured α-Al2O3 coatings exhibit the best performance in machining applications. For this purpose, the deposition conditions are constantly modified in order to achieve the most pronounced texture states of this type possible. Unfortunately, these distinct texture states push the supporting analytical methods, such as conventional sin²ψ residual stress analysis, to their limits. Other, more mathematically demanding techniques based on pattern decomposition then show their full strength and make it possible to go deeper without having access to time-consuming and expensive synchrotron diffraction methods. The work presented focuses on the residual stress state modified by texture control in α-Al2O3 hard coatings in the as-deposited state. The direct interrelation between the texture characteristics and the development of residual stresses is shown. In addition, the effect of sandblasting on the layer types was examined. The resulting superposition of two opposing stress states could be resolved.