Investigation of mechanical properties of fly ash and Al2O3 reinforced A356 alloy matrix hybrid composite manufactured by improved stir casting

The present work investigates mechanical properties of A356-alumina, A356-fly ash and A356-hybrid composite. Hybrid reinforcement is produced by taking an equal amount of fly ash and alumina particles. The effect of alumina, fly ash and hybrid reinforcement in A356 alloy is studied to cope with a growing interest in composites containing low density and low cost reinforcements. To fabricate the composites stir casting technique is used by incorporating useful findings in the literature. Reinforcement content varied from 0 to 12% by weight in steps of 4%. The microstructure, density, porosity, microhardness, compression and tension tests are carried on A356 alloy and composites. The microstructure studies reveal that manufactured composites has refined grain structure. Addition of hybrid reinforcement increased diminutive density of composites with increasing reinforcement %. Porosity is found less in fly ash and hybrid reinforced composite. Microhardness is found maximum for the A356-12 wt% Al2O3 composite. The increase in compression and tensile strength is observed due to the addition of alumina, fly ash and hybrid reinforcement %. Finally, the TOPSIS analysis is carried out by developing a MATLAB program to investigate the effective reinforcement type and wt%. It is found that decision of reinforcement type selection changes according to different precedences.