A Micromechanical Study of Thermal Stress-Induced Deformation and Microcracking in Ceramic-Metal Multiphase Solid Systems

基于从细观力学角度研究材料力学行为的“本征应变”理论(T.Mura：Martinus Nijhoff出版社，海牙，1982)，我们研究了一类在金属基质中含有陶瓷纤维或颗粒的非均匀固体系统中发生变形和断裂过程的机制。在整个研究过程中，我们强调了由于陶瓷和金属相热机械性能失配而产生的内应力所起的作用。我们所处理的课题包括：1)考虑金属相塑性的应力和应变场分析，2)具有完全结合和完全脱粘相界面的系统的有效热弹性性质(弹性常数和热膨胀系数)的预测，3)加工硬化和恢复过程的模拟，以及4)等温和热循环条件下蠕变本构方程的推导。针对最后一个课题，还进行了一些实验。最后讨论了本研究对功能梯度材料(FGM)设计的启示。

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, and4) 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.