The manufacture and characterization of aluminum alloy metal matrix nano composites

In this research the Composites of A356- Nano Al2O3 reinforced with different Wt. % were fabricated by(semi solid) double stir casting technique in order to improve the wettability and distribution of reinforcement particles within the matrix,. Semi-solid stir casting (SSC) techniques have proven useful in the mass production of high integrity castings for the automotive and other industries. In this process, the A356 aluminum alloy is heated to above its molten temperature. The melt is then cooled down to (5800C) a temperature between the liquid and solid points to a semi-solid state. At this point the preheated Nano Al2O3 reinforcement particles are warped with aluminum foil added and mixing at 450 r. p.m. the slurry is heated to a fully liquid state once again and mixed thoroughly for 30 mints. After applying Full heat treatments (T6) on a part of cast Nano composite ingots will provide for the samples; solution treatment consist of heating in an electrical furnace at 5400C (±10C) for 6 hours and then quenching in water at room temperature. The Artificial aging treatment done at 1800C for 3 hours. The effect of heat treatment (T6) on the microstructure and mechanical properties of the as caste and A-356 aluminum matrix composites was studied. The microstructure,porosity and distribution of Al2O3 nanoparticles for all samples A356 alloy were studied by optical microscope (OM) equipped with image analyzer, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), Also, the hardness and tensile strength of samples was investigated. The results showed, after full heat treatment the microstructure consists of hard intermetallic Mg2Si. The structure of the eutectic Si form to crash and spheroid sing and the Si particle become rounded). Significant agglomeration can be found in composites with different reinforcement percentage Nano particles Al2O3. Porosity will increase with the increase in the volume fraction of Nano Al2O3.Hardness, yield strength and tensile strength increase, but the elongation decreases with the increase in the wight fraction of the Al2O3 particles, indicating that increasing the wight fraction of the Al2O3 particles can improve the strength but degrade the plasticity of the composites. The mechanical strength of composite A356 alloy increased considerably by combining T6 heat treatment and different Wt. % of Nano- Al2O3 particle reinforced aluminum alloy.