Effect of Time-Dependent Matrix Behavior on the Evolution of Processing-Induced Residual Stresses in Metal Matrix Composites

The usefulness of load-relaxation experiments in investigating the need for rate-dependent matrix material models for predicting the processing-induced residual stresses in metal matrix composites (MMCs) is examined in this study. The experimental data is used in the selection of the appropriate constitutive equations for modeling the cooling process after composite consolidation. Boron/ Al-2024 MMC is chosen as the model material system. Bodner-Partom unified model and a classical creep-plasticity model based on the relaxation experiments are used to represent the rate-dependent behavior of Al-2024. The results show that conventional B-P model based on purely monotonic strain-rate tests is not able to capture the inelastic strain variations under practical cooling conditions. The classical creep-plasticity model has been shown to be an effective alternative for this purpose as it considers load-relaxation data while deriving the material constants for the constitutive equations.