Mechanisms of cavity shrinkage by static annealing in a high strain rate superplastic Si3N4p/Al-Mg-Si composite

Effects of static annealing on post-deformation properties and cavitation are examined in a high strain rate superplastic Si3N4p/Al-Mg-Si composite and the mechanisms of cavity shrinkage by static annealing are investigated. Post-deformation tensile properties were sufficiently recovered by static annealing. The experimental shrinkage rate of large cavities was in agreement with the value predicted by the diffusion-controlled shrinkage model. However, many small cavities still remained in the annealed samples. This is probably attributed to the low mass transfer rate by interface diffusion.