Anelastic Behavior Modeling of SiC Whisker-Reinforced Al2O3

Anelastic recovery during creep deformation of a whisker-reinforced Al2O3 matrix is examined in order to study the complex interactions of the reinforcement network with the matrix. In this paper, the finite-element method is used to model the elastic and creep properties of a representative volume element during creep deformation. Two types of unit cells are investigated. The first is a three-dimensional (3D) unit cell in which randomly oriented short fibers do not contact each other. The second case examined is a 2D cell within which fibers are aligned regularly so as to percolate through the unit cell. Simulation results from the 3D model verify the necessity of a percolating network for the anelastic recovery. Results from the 2D model show that anelastic recovery is attributed more to whisker bending, rather than to contact effects between fibers of the whisker network. Finally, FEM simulations of the maximum recoverable strain and characteristic relaxation time are found to be in good agreement with an analytical model recently developed by Wilkinson and Pompe, which is based on the application of Euler's beam theory in a 2D visco-elastic unit cell.