Crack propagation during Vickers indentation of zirconia ceramics

A numerical approach to study the crack propagation in symmetric step-wise graded Alumina/Zirconia composites subjected to a residual stress field is presented in this work. The finite element method is used to calculate the stress intensity factor for cracks developing from the surface and to determine the effects of the thermal residual stresses. The results show that a suitably conceived stacking sequence induces in the laminate a residual stress field able to provide increased toughness and reliability of the structure by making the crack propagation stable below a given threshold stress. Moreover a lower bound on stress, below which no crack propagation occurs, can be identified.

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Influence of Shielding on the Subcritical Crack Propagation in Zirconia Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.206-213.691 ◽

2001 ◽

Vol 206-213 ◽

pp. 691-694

Author(s):

Daniel Casellas ◽

Luis Llanes ◽

Marc Anglada

Keyword(s):

Crack Propagation ◽

Zirconia Ceramics ◽

Subcritical Crack Propagation

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Effects of the Thermal Residual Stress Field on the Crack Propagation in Graded Alumina/Zirconia Ceramics

Functionally Graded Materials VIII - Materials Science Forum ◽

10.4028/0-87849-970-9.177 ◽

2005 ◽

pp. 177-182 ◽

Cited By ~ 1

Author(s):

P. Vena ◽

D. Gastaldi ◽

R. Contro

Keyword(s):

Residual Stress ◽

Stress Field ◽

Crack Propagation ◽

Thermal Residual Stress ◽

Residual Stress Field ◽

Zirconia Ceramics

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Strain analysis in composite ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144012 ◽

1986 ◽

Vol 44 ◽

pp. 494-497

Author(s):

W. M. Kriven

Keyword(s):

Strain Field ◽

Strain Analysis ◽

Processing Temperature ◽

Transformation Toughening ◽

Zirconia Ceramics ◽

Volume Increase ◽

Analysis Technique ◽

Fundamental Understanding ◽

Contrast Analysis ◽

Elastic Strain Field

Significant progress towards a fundamental understanding of transformation toughening in composite zirconia ceramics was made possible by the application of a TEM contrast analysis technique for imaging elastic strains. Spherical zirconia particles dispersed in a large-grained alumina matrix were examined by 1 MeV HVEM to simulate bulk conditions. A thermal contraction mismatch arose on cooling from the processing temperature of 1500°C to RT. Tetragonal ZrO2 contracted amisotropically with α(ct) = 16 X 10-6/°C and α(at) = 11 X 10-6/°C and faster than Al2O3 which contracted relatively isotropically at α = 8 X 10-6/°C. A volume increase of +4.9% accompanied the transformation to monoclinic symmetry at room temperature. The elastic strain field surrounding a particle before transformation was 3-dimensionally correlated with the internal crystallographic orientation of the particle and with the strain field after transformation. The aim of this paper is to theoretically and experimentally describe this technique using the ZrO2 as an example and thereby to illustrate the experimental requirements Tor such an analysis in other systems.

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