Mechanical properties of fine ceramic particle-reinforced aluminum composites produced by high-energy milling

In order to develop particle-reinforced aluminum composites with advanced properties, the effect of submicron ceramic particles dispersed by high-energy milling was investigated. The composites consisted of commercially pure aluminum matrix and 0.5μm Al2O3 particles; the volume fraction of particles ranged from 0 to 30%. The composites showed high tensile strength paticularly at elevated temperatures and good resistance to softening; the composite with 30vol% Al2O3 particles had a tensile strength of 20kgf/mm2 at 400°C. This excellent heat-resistance of the composites was considered to arise from the very fine dispersoids of aluminum oxides and carbides generated during high-energy milling. The composites also exhibited good ductilities under compressive conditions. The dispersed Al2O3 particles increased elastic modulus and decreased thermal expansion coefficient. The wear resistance of the composites was also improved by Al2O3 particles.