Abstract:
Dynamic compression tests of the 15% (volume fraction) SiC
p/Al composite were carried out by separate Hopkinson compression bar device, and the dynamic mechanical properties and microstructure evolution of the composite at high strain rates of 500-2 000 s
-1 were studied. With the experimental data, stress-train curves were predicted by the Johnson-Cook constitutive model containing the adiabatic temperature rise softening term relating to strain rate and plastic strain, and the predicted results of the model were compared with the experimental results. The results show that the strain rate strengthening effect of the composites was not obvious, but the composites showed a significant strain strengthening. With increasing strain rate, the deformation types of the composite changed from uniform deformation to localized deformation, the fracture of the reinforcing particles was serious, and the adiabatic shear bands were formed and extended in local areas. The relative error between the stress-strain curves calculated by the modified Johnson-Cook constitutive model containing the adiabatic temperature rise softening term and the experimental results was less than 17%.