A theoretical study on the temperature-dependent yield strength of in-situ particle and whisker hybrid-reinforced metal matrix composites

The hybrid effect observed in hybrid-reinforced composites presents a promising opportunity to further enhance the mechanical properties of composites. In this study, a theoretical model is established to determine the yield strength of in-situ particle and whisker hybrid-reinforced metal matrix composites by considering the mechanisms of stress transfer strengthening and grain boundary strengthening. And the hybrid effect is well characterized. The model is then extended to incorporate temperature dependence, considering changes in key parameters as temperature varies. With only one readily available experimental reference point, yield strength at different temperatures can be conveniently predicted. Satisfactory agreements are achieved between model predictions and experimental data. Moreover, quantitative analyses are performed to examine the hybrid effect at various temperatures and reinforcement volume fractions. The results show that the hybrid effect increases significantly with the increasing reinforcement volume fraction, but as the temperature increases, the hybrid effect decreases in proportion to the matrix yield strength.