Data Collection Requirements for the Analysis of Residual Stress in Polycrystalline Coatings

Abstract

Residual stress in polycrystalline coatings can be determined by X-ray diffraction. The data collection requirements are summarized and evaluated in this paper. First, general requirements for stress measurements are described. Then, requirements related to the diffraction geometry and the specimen manipulation are considered. Finally, requirements with respect to specimen characteristics, including various coating-substrate combinations are presented. Polycrystalline coatings can be nanocrystalline, randomly orientated or highly textured. The substrates can be of any nature: amorphous, polycrystalline or single crystal. The complete set of requirements leads to a measurement advice for a particular coatingsubstrate specimen, which includes the choice of diffraction geometry and the data collection strategy. Based on two complementary test cases it is demonstrated that the set of rules is complete and that they can be applied to any type of polycrystalline specimen.