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 nee d far rate-dependent matrix material models for predicting the process ing-induced residual stresses in metal matrix composites (MMCs) is exa mined in this study, The experimental data is used in the selection of the appropriate constitutive equations for modeling the cooling proce ss after composite consolidation. Boron/Al-2024 MMC is chosen as the m odel material system. Bodner-Partom unified model and a classical cree p-plasticity model based on the relaxation experiments are used to rep resent the rate-dependent behavior of Al-2024. The results show that c onventional B-P model based on purely monotonic strain-rate tests is n ot able to capture the inelastic strain variations under practical coo ling conditions. The classical creep-plasticity model has been shown t o be an effective alternative for this purpose as it considers load-re laxation data while deriving the material constants for the constituti ve equations.