Papers by Author: Arnold C. Vermeulen

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Authors: Arnold C. Vermeulen, Rob Delhez, T.H. de Keijser, Eric J. Mittemeijer
Authors: Arnold C. Vermeulen
Abstract: The alignment of a ¼-circle Eulerian cradle is discussed. The method is based on diffraction and uses a special alignment tool and a stress-free powder sample. A new profile shape function is introduced to describe better distorted diffraction peaks.
Authors: Arnold C. Vermeulen
Authors: Arnold C. Vermeulen, Detlev Götz
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.
Authors: Nicholas Norberg, Arnold C. Vermeulen
Abstract: Collecting reliable data is crucial in the research of residual stresses in thin films using X-ray diffraction. The parallel beam geometry has advantage of reliability compared to focusing beam geometry. Though care must be taken to the alignment. A small alignment error may cause a significant error in the stress value. We will show the sensitivity for the misalignment of the parallel beam optics, discuss requirements on hardware alignment and demonstrate a software correction for the presence of remaining hardware errors.
Authors: J.G.M. Van Berkum, Arnold C. Vermeulen, Rob Delhez, T.H. de Keijser, Eric J. Mittemeijer
Authors: Arnold C. Vermeulen, Rob Delhez
Abstract: All methods of analyzing the broadening of XRD line profiles have to take into account two basic effects: broadening by the instrument - including the X-ray spectrum - and the characteristics of broadening by size effects and by lattice defects - including their interaction. These effects are handled in practice by a wide range of auxiliary assumptions. In this paper these assumptions and their quality with respect to "appropriateness of purpose" are listed and compared. By systematic ranking of these assumptions in accordance with their quality, a 2-dimensional map can be constructed that visualizes the differences in the quality of the assumptions. This 2-dimensional map brings a new viewpoint to the various methods for line profile analysis, because it enables a qualitative comparison of the assumptions of existing methods and new developments.
Authors: Arnold C. Vermeulen
Abstract: The sensitivity of various combinations of optics to alignment errors is investigated. A large number of tests with varying specimen displacements and incident beam misalignments are performed for both line and point focus residual stress optics combinations. This investigation includes experiments with mixed combinations of typical “focusing beam optics” and “parallel beam optics”. It is verified if the peak positions are either sensitive to height errors like for the focusing beam geometry or insensitive like for the parallel beam geometry. The peak position sensitivity is classified for all combinations of incident beam and diffracted beam optics modules.
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