Calculations of single crystal elastic constants for yttria partially stabilised zirconia from powder diffraction data

Abstract

Articles you may be interested inGrain and the concomitant ferroelectric domain size dependent physical properties of Ba0.85Ca0.15Zr0.1Ti0.9O3 ceramics fabricated using powders derived from oxalate precursor route Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of timeof-flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11 ¼ 451, C33 ¼ 302, C44 ¼ 39, C66 ¼ 82, C12 ¼ 240, and C13 ¼ 50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent. V C 2014 AIP Publishing LLC. [http://dx.

Investigations into the interface failure of yttria partially stabilised zirconia - porcelain dental prostheses through microscale residual stress and phase quantification

“…A distinct variation in Young's modulus is also observed within the first 10 μm of the interface, with a reduced stiffness found in four measurements closest to the interface. Monoclinic YPSZ is known to have a smaller bulk elastic modulus than tetragonal YPSZ, and this may be the origin of this behaviour [49]. The impact of elemental diffusion may also be influencing the near-interface YPSZ state and mechanical response, with diffusion of silicon being observed up to 2 − 3 μm into the YPSZ.…”

Diffraction-based determination of single-crystal elastic constants of polycrystalline titanium alloys

“…The singlecrystal elastic constants of any polycrystalline material may then be determined by an inversion of the usual calculations applied in the residual stress analysis and fitting by a 2 -minimization technique. The feasibility of such an ISSN 1600-5767 approach was demonstrated by Hauk & Kockelmann (1979) and later applied by various authors (Gnä upel-Herold et al, 1998;Kisi & Howard, 1998;Singh et al, 1998;Howard & Kisi, 1999;Matthies et al, 2001;Fré our et al, 2005;Stebner et al, 2013;Lunt et al, 2014;Kim et al, 2016) for alloys and ceramics by diffraction under tensile stress or compression. This technique is of particular relevance for any engineering material which cannot be obtained as a single crystal, especially multiphase or highly twinned materials.…”

Density functional theory of cubic zirconia and 6–15 mol% doped yttria-stabilized zirconia: structural and mechanical properties

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