Fabrication of Al alloy matrix composite reinforced with subsive-sized Al2O3 particles by the in situ displacement reaction using high-energy ball-milled powder

High-energy mechanical milling (HEMM) and sintering were employed to fabricate an Al alloy matrix composite reinforced with subsive-sized Al2O3 particles. Al–(Mg, Cu, Si)–SiO2, composite powders were prepared by HEMM. Nano-sized SiO2 particles embedded in Al–(Mg, Cu, Si) matrix particles were obtained by HEMM. Al-based metal matrix composite reinforced with subsive-sized Al2O3 particles was fabricated successfully by sintering at 650 and 750 °C for 2 h using milled powder. Subsive-sized Al2O3 particles and eutectic Si were formed by in situ displacement reaction between Al and SiO2 during sintering, and homogeneously distributed in the Al–Si–(Mg, Cu) matrix. The flexural strength of the sintered specimen (1.2 GPa) using 8 h milled powder was about four times as the sintered specimen using as-mixed powder.