| Research Abstract |
Based on the theory of "eigenstrains" (T. Mura: Micromechanics of Defects in Solids, Martinus Nijhoff Publishers, The Hague, 1982) which has been developed for the study of the mechanical behavior of materials from the micromechanics point of view, we have investigated the mechanisms of deformation and fracture processes occurring in a class of inhomogeneous solid systems which contains ceramic fibers or particulates in a metal matrix. Throughout this research we emphasize the role played by internal stresses due to the mismatch in thermomechanical properties between the ceramic and metal phases.
The subjects we have dealt with are:
1) analysis of stress and strain fields by taking the metal phase plasticity unto account,
2) prediction of effective thermoelastic properties (elastic constants and thermal expansion coefficients) for systems with perfectly bonded and perfectly debonded phase interfaces,
3) modeling of work-hardening and recovery processes, and
4) derivation of constitutive equations for creep under isothermal and thermal-cycling conditions.
In relation to the last subject, some experiments have also been made. Finally, implications of this research in the design of Functionally Gradient Materials (FGM) are discussed.
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