Strength and electrical conductivity of Al composites with nanocrystalline W alloy reinforcements: Experiments and modeling

Abstract

This work reports the strength and electrical conductivity of a novel Aluminium metal matrix composite (MMC) containing nanocrystalline W-20Ti alloy dispersoids. The hot-pressed Al-4 vol. %(W-20Ti) composite exhibited higher compressive yield strength than Al-4 vol. %W and Al-4 vol. %SiC composites processed under similar conditions. The Al-W20Ti composite demonstrated a 10 % higher electrical conductivity than the Al-SiC composite which could be attributed to the metallic nature of the W-20Ti dispersion. Interestingly the W-20Ti alloy dispersions, demonstrating a microhardness of 18.6 GPa, exhibited better phase and chemical stability than the unmilled W during processing of their respective MMCs. Strengthening models revealed a significant contribution of thermal expansion mismatch induced stresses to the high strength of the Al-W20Ti system.