Transformation toughening
- 887 Downloads
- 456 Citations
Abstract
The thermodynamics of the constrained phase transformation is presented with particular reference to size effects introduced by surface phenomena concurrent with the transformation, e.g., the formation of solid-solid surfaces (twins, etc.) and solid-vapour surfaces (microcracks). It is shown that these surface phenomena not only introduce a size-dependent energy term into the total free-energy change, but also reduce the strain energy associated with the transformation, which can result in a transformation at a temperature where ¦ΔGc¦, the chemical free energy change, is less thanUse, the unrelieved strain energy associated with the constrained transformation. The results of this analysis lead to a phase diagram representation that includes the size of the transforming inclusion. This diagram can be used to define the critical inclusion size required to prevent the transformation and/or to obtain the transformation, but avoid one or more of the concurrent surface phenomena.
Keywords
Polymer Free Energy Phase Diagram Phase Transformation Energy ChangePreview
Unable to display preview. Download preview PDF.
References
- 1.
- 2.R. C. Garvie andR. T. Pascoe, in “Processing of Crystalline Ceramics” edited by H. Palmour III, R. F. Davis and T. M. Hare (Plenum Press, New York, 1978) p. 263.Google Scholar
- 3.
- 4.Idem, ibid. 6 (1977) 280.Google Scholar
- 5.T. K. Gupta, J. H. Bechtold, R. C. Kuznichi, L. H. Adoff andB. R. Rossing,J. Mater. Sci. 12 (1977) 2421.Google Scholar
- 6.
- 7.
- 8.A. Heuer andG. L. Nord, Jr, in “Electron Microscopy in Minerology” edited by H. R. Weuk (Springer-Verlag, Berlin, Heidelberg and New York, 1976) p. 274.Google Scholar
- 9.J. E. Bailey,Proc. Roy. Soc. 279A (1964) 395.Google Scholar
- 10.
- 11.
- 12.
- 13.K. K. Srivastava, R. N. Patil, C. B. Chandary, K. V. G. K. Gokhale andE. C. Subbarao,Trans. Brit. Ceram. Soc. 73 (1974) 85.Google Scholar
- 14.H. C. Scott,J. Mater. Sci. 10 (1975) 1527.Google Scholar
- 15.
- 16.J. D. Eshelby, in “Progress in Solid Mechanics” Vol. 2, edited by I. N. Sneddon and R. Hill (North-Holland Publishers, Amsterdam, 1961) p. 89.Google Scholar
- 17.R. C. Garvie,J. Phys. Chem. 69 (1965) 1238.Google Scholar
- 18.Idem, ibid. 82 (1978) 218.Google Scholar
- 19.F. F. Lange, in “Fracture Mechanics of Ceramics” edited by R. C. Brandt, D. P. H. Hasselman and F. F. Lange (Plenum Press, New York, 1974) p. 599.Google Scholar
- 20.Idem, in “Fracture Mechanics of Ceramics” Vol. 4, edited by R. C. Brandt, D. P. H. Hasselman and F. F. Lange (Plenum Press, New York, 1978) p. 799.Google Scholar
- 21.Y. M. Ito, M. Rosenblatt, L. Y. Cheng, F. F. Lange andA. G. Evans,Inter. J. Fracture, to be published.Google Scholar
- 22.
- 23.D. L. Porter, PhD thesis, Case-Western University (1977) (University Microfilms Int. Order No. 77-25185, p. 190).Google Scholar
- 24.
- 25.