High-strain-rate superplasticity of SiC_p/8090 aluminum composite

Superplastic tensile tests of a 17 vol.% SiCp/8090 Al-Li composite were carried out at strain rates ranging from 7.25 × 1-4s-1to 3.46 × 10-1s-1and at temperatures from 773 K to 873 K. A maximum elongation of 300% was obtained at a strain rate of 1.83 × 10-1s-1when tested at a temperature of 848 K which was slightly above the solidus temperature of the composite. The effect of a small fraction of liquid phase on high-strain-rate superplasticity was discussed. Finally, the activation energy of high-strain-rate superplastic deformation was calculated and high-strain-rate superplastic mechanism was discussed.