WS1d1 - TRANSFORMATION PLASTICITY AND ITS APPLICATION TO CERAMICS TOUGHENING
Review articleOpen access
1992/01/01 Simple chapter DOI: 10.1016/B978-0-08-037890-9.50033-8
ABSTRACTA constitutive Model of transformation plasticity is suggested based on micromechanics and thermodynamics consideration. The model takes into account both the dilatation and shear effects of phase transformation, and is capable of describing the plastic, pseudoelastic and shape memory behavior of structural ceramics during transformation under different temperatures. The constitutive element used, taken as a representative material sample, contains transformed grains or precipitates, as second phase inclusions embedded in an elastic untransformed matrix. Under some reasonable basic assumptions, the expressions of free energy are derived in a self–consistent manner by use of Mori–Tanaka's method, taking account of the interaction between the transformed inclusions. In the framework of Hill–Rice's constitutive theory with internal variables, the transformation criteria and incremental stress strain relations are derived. Theoretical predictions of the suggested constitutive relations are compared with the available experimental data of Mg–PSZ and Ce–TZP polycrystalline ceramics, and good agreement is obtained between theory and experiments. Moreover, the constitutive relations are used to predict toughening effect of transformation for ceramics and lead to excellent coincidence with experiments.
Request full text