Pattern decomposition for residual stress analysis: a generalization taking into consideration elastic anisotropy and extension to higher-symmetry Laue classes

Abstract

The residual stress state of ion‐conducting layers (yttria stabilized zirconia) and protective hard coatings (α‐aluminium oxide, titanium carbonitride) was investigated using X‐ray diffraction techniques. Its evaluation within the tetragonal, trigonal and cubic phases present was performed by a whole powder pattern decomposition procedure according to Pawley. Going beyond previous work, the applied refinements directly include the influence of elastic anisotropy on the residual stress results. Starting from the single‐crystal elastic coefficients, the X‐ray elastic constants according to the Voigt and Reuss models were calculated. Finally, the Neerfeld–Hill model as a generalization was implemented to introduce the hkl‐specific X‐ray elastic constants for calculating the residual stress magnitude within the least‐squares minimization routine. It was possible to resolve the residual stress state in stacked layers of different chemical and phase composition and to reproduce the results obtained by the classical χ‐ and ω‐inclination sin2Ψ techniques.

Strain, stress and stress relaxation in oxidized ZrCuAl-based bulk metallic glass

“…Accordingly, the XECs were obtained from the single-crystal elastic constants (SECs) for ZrO2, assuming elastic interaction according to Voigt, implying that all crystallites experience the same strain. Table 2 provides the SECs and, thus calculated XECs for cubic ZrO2 [40] together with the macroscopic Poisson ratio (ν) and Young's modulus (E). .…”