Compressive behavior of extruded SiCw/AZ91 at temperatures close to and above the solidus of the matrix alloy

摘要

Compressive deformation behaviors of extruded SiCw/AZ91 were investigated in Gleeble-1500 thermal simulator at temperatures from 743 K to 783 K and strain rates from 6.4x10~(-2) s~(-1) to 1.0x10~1s~(-1). Results showed that high strain rate sensitivity (～0.5) occurred during compression; deformation activation energy normalized by threshold stress was higher than the lattice self-diffusion activation energy of magnesium. Dynamic recovery (DRV) and dynamic recrystallization (DRX) took place during compression, which refined the grains. The increase of deformation energy was attributed to non-basal planes slip and climbing of dislocations and also the presence of liquid phase.