Elastic Anisotropy in Zirconia Single Crystals

Ingel, R. P.; Lewis, David

doi:10.1111/j.1151-2916.1988.tb05858.x

Cited by 150 publications

(61 citation statements)

References 21 publications

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“…The ®t to the strain±stress plots is exactly as before, but the extracted constants have a different interpretation. The results are included in Table 3, along with data from several literature sources collected together by Ingel & Lewis (1988). The scatter in single-crystal data from different sources is represented by estimated errors in brackets.…”

Section: Elastic Constants From a Single Diffraction Measurement And mentioning

confidence: 99%

Measurement of single-crystal elastic constants by neutron diffraction from polycrystals

Howard

Kisi

1999

J Appl Cryst

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The relationships of diffraction averaged elastic compliances for an ideally random polycrystal to the single-crystal elastic compliances are given, within the Reuss approximation, for crystal systems with orthorhombic and higher symmetry. For anisotropic materials, these diffraction elastic compliances are dependent on the reflection indexhkl. Expressions for the conventional elastic constants (Young's modulus, Poisson's ratio) are also given. A connection is made to the `X-ray elastic constants' used for diffraction-based measurements of residual stress. The relationships are used to calculate diffraction averaged constants for comparison with neutron diffraction data recorded from samples under applied uniaxial stress. The Reuss approximation works well for materials with the capacity for plastic deformation, such as metals and transformation toughening ceramics, whereas for other materials the Voigt–Reuss–Hill approximation gives better results. Based on the given relationships and experimental determinations of the diffraction elastic compliances for polycrystalline materials, a method is developed for determining the single-crystal elastic constants. The method for estimating single-crystal compliances is demonstrated here by application to extant data on Ni–Cr–Fe and Ti–6 wt% Al–4 wt% V alloys, and new measurements on cubic zirconia. It has been applied very recently [Kisi & Howard (1998).J. Am. Ceram. Soc.81, 1682–1684] to determine the previously unknown elastic constants for a tetragonal zirconia.

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Section: Elastic Constants From a Single Diffraction Measurement And mentioning

confidence: 99%

Measurement of single-crystal elastic constants by neutron diffraction from polycrystals

Howard

Kisi

1999

J Appl Cryst

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“…These are mostly associated with providing accurate determination of their crystalIogTaphic orientation, which determines the anisotropy of their properties. For example, it has been shown in [10] how the elasticity modulus of a cubic crystal of zirconium dioxide depends on the direction of its measurement in the crystal lattice. In this case the maximum value of the elasticity modulus corresponded to the direction <100> and was approximately equal to 360 GPa.…”

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confidence: 98%

Zirconia crystals with yttrium and cerium oxides

et al. 1995

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Results obtained for a new material, namely, zirconia crystals stabilized by Y203 and CeO2 and containing a technological addition of neodymium oxide, tested at room temperature are described. Special features of the surfaces of the crystal blocks grown and the distribution of the additions introduced into the charge over their height are investigated. The dependences of the amounts of the stabilizing components and the fracture properties of the investigated material on its strength are determined. Certification results for the mechanical characteristics of the material are presented (mean four-point bending strength 1250 MPa, crack resistance in bending of a notched bar 11.43 MPa-m ~n at an elasticity modulus of 366 GPa for the crystallographic direction <100>). The crystals are investigated in the crystallographic plane { 100} by applying Vickers and Knoop indenters, and their hardness at different loads (beginning with 0.1 N) is determined. It is established that zones of phase transformations are formed near the indentations in addition to radial and lateral cracks. Problems of change in the specific features of the mechanical behavior of the crystals with change in the valence of cerium (most experiments were conducted for Ce203 ), with the heat treatment, etc. are considered. The results are analyzed using data of fractographic investigations and the new data obtained in tests of similar crystals partially stabilized by yt~ium and terbium oxides.It was established in the early 1980s [1] that crystals of partially stabilized zirconia possess relatively high mechanical parameters and other advantages that make them applicable for various purposes at temperatures up to 1600°C. However, these materials are not used in industry, although a technology for producing coarse crystals with high strength and crack resistance has been devised [2]. This can be explained by the fact that potential users have insufficient information on these crystals and that it is sometimes impossible to prepare materials with uniform structure and properties in an amount sufficient for practical purposes. In growing the crystals it is difficult to eliminate the appearance of cracklike defects, and in long-term storage they sometimes break spontaneously due to internal stresses. This shows that attention to investigating zirconia crystals for structural applications is insufficient. This especially concerns the interdependence of the technological regimes for preparing them, the phase composition, the structure, the laws governing their mechanical behavior, etc. On the whole, data that would make it possible to improve the production technology for these crystals and realize their potentialities are very scarce. As a continuation of previous work in this field [3], we present results of an investigation of crystals whose charge, in addition to zirconia (ZrO 2 ), contained Y203 and CeO 2 plus neodymium oxide 3 (Nd203 ) as a technological addition. These crystals were denoted Y-Ce-PSZ-K.Materials and methods. The experiments were conduct...

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“…5) in the (001) plane for crystals of the PSZ type virtually coincides with the analogous change in the elasticity moduli in cubic ZrO 2 crystals [25] in the same plane. In cubic crystals the elasticity moduli in the (001) plane are about 360 GPa for the (001) directions and 190 -200 GPa for the (011) directions.…”

Section: Discussion Of Resultsmentioning

confidence: 51%

“…The possible changes in the elasticity modulus in crystals [25] for different orientation of the indenter on the surface of the specimens should also be taken into account in the calculations. The coefficients M and N in Table 3 were obtained for E = 209, 350, and 200 GPa for 3Y-TZP, 3Y-Tb-PSZ-K ((100)), and 10Y-Tb-PSZ ((110)), respectively.…”

Section: Discussion Of Resultsmentioning

confidence: 99%