Fabrication of as-cast Al matrix composite reinforced by Al2O3/Al3Ni hybrid particles via in-situ reaction and evaluation of its mechanical properties

In this work, an attempt was made to synthesize Al2O3/Al3Ni hybrid reinforcement particles in Al-matrix to fabricate an AMC using stir casting technique. The molten metal was stirred while NiO powder was injected into the melt using blowing inert argon. During the production process, aluminothermy reaction took place explosively. The reaction products were alumina as the first reinforcements and pure nickel metal. This reaction was followed by the formation of eutectic structure of (Al3Ni)eut at 1113 K. Adiabatic temperature of aluminothermy reaction was obtained 1923 K. A reaction occurs between aluminum and nickel at the melting point of aluminum during the solidification and Al3Ni intermetallic compound is formed which acts as the second reinforcement. The presence of Al2O3 and Al3Ni in the matrix was verified by EDS/XRD analysis. Significant increase happened in UTS, hardness, and microhardness values. It is due to the presence of created reinforcement particles uniformly dispersed in Al matrix.