Experimental study of the rate-sensitivity of SiCp/Al composites and the establishment of a dynamic constitutive equation

In the present paper, loading and loading–unloading tests of SiCp/Al (SiC-particle-reinforced aluminium alloy) composite have been carried out in a self-designed tensile impact apparatus, and quasi-static tensile tests have been performed on a Shimadzu-5000 testing apparatus. Stress/strain curves of composites in the strain-rate range from 0.002 to 1000 s−1 have been obtained. The experimental results show that the SiCp/Al composite is a rate-sensitive material, the yield strength, ultimate strength and failure strain all increasing with increasing strain rate. On the basis of these experimental results and Eshelbyʹs equivalent inclusion method, a self-consistent model has been developed to predict the non-linear deformation of SiCp/Al at high strain rate. In this model, the ceramic particles are taken to be elastic, of uniform size, spherical and uniformly distributed in the matrix, and the stress/strain behavior of the alloy matrix is assumed to be power-law strain hardening and modified power-law strain rate hardening of the Ramberg–Osgood type. Comparison between the model calculation and experimental results for the strain rate dependence of SiCp/Al shows good agreement.