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Rietveld‐based energy‐dispersive residual stress evaluation: analysis of complex stress fields σ ij ( z )
Author(s) -
Apel Daniel,
Klaus Manuela,
Genzel Martin,
Genzel Christoph
Publication year - 2014
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576713034158
Subject(s) - residual stress , diffraction , crystallite , residual , materials science , rietveld refinement , stress (linguistics) , peening , physics , mathematics , optics , composite material , metallurgy , algorithm , linguistics , philosophy
A method for the evaluation of strongly inhomogeneous residual stress fields in the near‐surface region of polycrystalline materials is introduced, which exploits the full information content contained in energy‐dispersive (ED) diffraction patterns. The macro‐stress‐induced diffraction line shifts Δ E ψ hkl observed in ED sin 2 ψ measurements are described by modeling the residual stress state σ ij ( z ) in real space, based on Rietveld's data analysis concept. Therefore, the proposed approach differs substantially from currently used methods for residual stress gradient analysis such as the `universal plot' method, which enable access to the Laplace stress profiles σ ij (τ). With the example of shot‐peened samples made of either 100Cr6 steel or Al 2 O 3 , it is demonstrated that the simultaneous refinement of all diffraction patterns obtained in a sin 2 ψ measurement with hundreds of diffraction lines provides very stable solutions for the residual stress depth profiles. Furthermore, it is shown that the proposed evaluation concept even allows for consideration of the residual stress component σ 33 ( z ) in the thickness direction, which is difficult to detect by conventional sin 2 ψ analysis.