ABSTRACT
A study of the effects of pressure on micro-structure and mechanical properties of die cast aluminum alloys A1350 and A380 was carried out and subsequent analysis made. Pressure was regulated at various levels in the die cast machine. Both alloys were cast into samples each under different applied pressures. The mechanical properties of both alloys were tested and microstructure analysis was done and the results for both tests were compared for both alloys. The results obtained show hardness, tensile strength, yield strength and impact strength of both alloys varied with applied pressure in the casting process. The hardness values increased with applied pressure but not too significantly from 76 to 85 HRN for A380 alloy and 77 to 86 HRN for A1350 alloy as pressure rose from 350 to 1400kg/cm2. The yield strength of both alloys also increased with applied pressure. The impact strength and elongation both decreased with applied pressure in both alloys. Also the micro-structure analysis carried out on both alloys showed structural changes in the morphologies of both alloys as some appeared granullar, lamellar, coarse e.t.c from pressure 350 to 1400kg/cm2. Also as the pressure increased, the grains became finer and porosity decreased. Models were developed and for all the models developed, a close relationship with the experimental results were underlying in view of the small errors generated by them and can be used to predict the experimental values of this research.