The Size Effect of Pail sic on Activation Energy for High-Strain-Rate Superplastic Row in Powder-Metallurgy Processed 2124 Al Composites

摘要

The true activation energies revealed after theincorporation of threshold stress for plastic flow were comparedbetween the two PM superplastic 20 percent SiC_p/2124 Alcomposites with different reinforcement sizes. There was largediscrepancy between the activation energy values, though thevolume fraction of SiC was same for the two composites. Thecomposite with the finer reinforcement size (3#mu#m) exhibitedmuch larger activation energy value than the other with therelatively coarse SiC particulates (8#mu#m). This difference inthe true activation energy was attributed to the difference in theSiC/Al interface area per unit volume of composite.