Compressive behaviour of Al-based hybrid composites reinforced with SiC whiskers and SiC nanoparticles

The compressive behavior of (17 vol.%SiCw + 3 vol.%SiCp)/2024Al (W₁₇P₃) hybrid composites and 20 vol.%SiCw/2024Al (W₂₀) composites fabricated by squeeze casting was studied in the temperatures range from 298 K to 793 K with the strain rate of 0.01 s^-1. The peak flow stress of the W₁₇P₃ hybrid composites is higher than that of the W₂₀ composites at room temperature and at elevated temperatures, which indicates that the nanoparticle is more effective on the improvement of peak flow stress of the hybrid composites by Orowan strengthen mechanism. Whisker reinforcement is more effectively reinforced the composites as temperature increasing. However, the higher flow stress of the hybrid composite deformed above the solidus is related to the formation of fine subgrains according to Hall-Petch formula. TEM observation indicates that the dynamic recrystallization for the hybrid composites occurs so as to establish the subgrain with 250-300 nm in the hybrid composites.