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Transformation Plasticity and Transformation Toughening in Mg-PSZ and Ce-TZP

Published online by Cambridge University Press:  25 February 2011

I-Wei Chen  and
P. E. Reyes-Morel
I-Wei Chen
Affiliation:
University of Michigan, Ann Arbor, Michigan 48109-2136
P. E. Reyes-Morel
Affiliation:
University of Michigan, Ann Arbor, Michigan 48109-2136
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Abstract

The constitutive behavior of transformation plasticity in single phase fine grain Ce-TZP and polyphase coarse grain Mg-PSZ was studied. A material independent pressure sensitivity and a microstructure dependent strain rate sensitivity and temperature sensitivity were found to be associated with the transformation yield stress. Autocatalysis of various extent operates in all cases, forming broad macroscopic shear bands in TZP and fine crystallographic slip bands which terminate at grain boundaries in PSZ. Transformation plasticity is apparently athermal near the Mb temperature in TZP, but not in PSZ except in brittle fracture. A strong crystallographic texture of the transformed phase develops during deformation. These results are analyzed in terms of a shear-dilatant yield criterion and a rate equation which account for stress assistance in martensitic transformation. An elastic-plastic fracture mechanical model is developed to estimate both the shear and dilatation contributions to the transformation plastic work in the crack tip plastic zone. On the basis of approximately equal shear and dilatation contributions to transformation plasticity, the model predicts a transformation zone height which is four times that of the previous model, and a toughness increment which is two times that of the previous model. These predictions are found in good agreement with the reported toughness-zone size relationship. The effect of temperature and chemical stability on toughness is also rationalized.

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Articles
Information
MRS Online Proceedings Library (OPL) , Volume 78: Symposium E – Advances in Structural Ceramics , 1986 , 75
Copyright
Copyright © Materials Research Society 1987

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References

REFERENCES

1. Chen, I-Wei, ”Mechanisms of Transformation and Transformation Plasticity in ZrO2-Containing Ceramics”, in Zirconia Ceramics 4, 55–79, eds Somiya, S. and Yoshimura, M.. Uchida Rokakuho Pub. Co. Tokyo, Japan(1985).Google Scholar
2. Chen, I-Wei, ”Implications of Transformation Plasticity on Deformation and Fracture Control of Zirconia-Containing Ceramics”, inZirconia Ceramics 7, 49–63, eds Somiya, S. and Yoshimura, M., Uchida Rokakuho Pub. Co. Tokyo, Japan(1986).Google Scholar
3. Chen, I-Wei and Reyes-Morel, P.E., “Implications of Transformation Plasticity in ZrO2-Containing Ceramics: I, Shear and Dilatation Effects”, J. Am. Ceram. Soc. 69 [3] 181–189 (1986).Google Scholar
4. Reyes-Morel, P.E., “An Experimental Study of Constitutive Relations of Transformation Plasticity in Zirconia-Based Ceramics”, Ph.D. Thesis, Department of Nuclear Engineering, Massachusetts Institute of Technology, June (1986).Google Scholar
5. Evans, A.G. and Heuer, A.H., ”Review-Transformation Toughening in Ceramics: Martensitic Transformation in Crack-tip Stress Fields”’ J. Am. Ceram. Soc., 63 [5–61] 241–248 (1980).Google Scholar
6. Virkar, A.V. and RJL.Matsumoto, K., “Ferroelastic Switching as a Toughening Mechanism in Tetragonal Zirconia”, J. Am. Ceram. Soc., 69 [10] C–224(1986).CrossRefGoogle Scholar
7. Chen, I-Wei, Chiao, Y-H. and Tsuzaki, K., “Statistics of Martensitic Nucleation”, Acta Metall., 33 [10]8 1847–59 (1985).CrossRefGoogle Scholar
8. Morel, P.E. Reyes, Bowman, K.J. and Chen, I-Wei, this volume.Google Scholar
9. Lankford, J.,”Plastic Deformation of Partially Stabilized Zirconia”, J. Am. Ceram. Soc., 66 [11] C–212 (1983).CrossRefGoogle Scholar
10. Olson, G.B. and Cohen, M., “A General Mechanism of Martensitic Nucleation: Part III. Kinetics of Martensitic Nucleation”, Metall. Trans., 7A [12],1915–1923 (1976).CrossRefGoogle Scholar
11. Hutchinson, J.W., “On Steady Quasi-static Crack Growth”, Harvard University Report, Division of Applied Sciences, DEAP S-8, April (1974).Google Scholar
12. McMeeking, R.M. and Evans, A.G., ”Mechanics of Transformation- Toughening in Brittle Materials”, J. Am. Ceram. Soc., 65 [5] 242–6 (1982).Google Scholar
13. Budiansky, B., Hutchinson, J.W. and Lambropoulos, J.C., “Continuum Theory of Dilatant Transformation Toughening in Ceramics”, Int. J. Solids Struc., 19 [4] 337–55 (1983).Google Scholar
14. Becher, P.F., Swain, M.V., and Ferber, M.K., “Relation of Transformation Temperature to the Fracture Toughness of Transformation Toughened Ceramics,” J.Mater.Sci. 22 [1] 71–84 (1987).Google Scholar