After conducting the experiment the graph was plotted between the Stress and Strain of the three specimens. From the above graph it is observed that, out of the three materials, steel is having highest tensile stress value and that is why it can withstand higher tensile load than other two given materials. Also, the difference of its initial and final value of radius is least as compared to other two materials. While the Steel withstand higher tensile load, on the other hand the Aluminum withstands the lowest. Among all three the ultimate tensile stress of Steel is noted to be the highest. Changes in length indicate the ductility of the material when loaded. There were large amounts of necking observed in Steel than there was in Aluminium. Precipitation hardening done to Aluminium and its alloys hinders the elongation of the specimen.From another graph which is of displacement vs. force, it can be concluded that the material with low tensile loading (Aluminum) capacity deforms more as compared to other having higher tensile loading capacity (Steel). So through this experiment, it is clear that the materials having high value of young’s modulus are having greater stiffness under elastic loading while materials having low young’s modulus value are more flexible and changes shape considerably.Conclusion:- Many engineering applications that reuire high tensile strength normally use mild steel. This is because of the crystalline structure of mild steel that allows it to withstand high axial loads before fracture can occur. Aluminium however has found many uses in designs that reuire low density materials life in aerodynamics and some motor vehicles. Aluminium experiences high ductility rates compared to steel and have therefore low level values of young’s Modulus, a factor that determines deflections in structural components. This experiment therefore reflects close relationship of tensile strength to the theoretically determined data.