Sharif Digital Repository

LM13 Aluminum alloys contain Silicon, Copper, magnesium and Nickel. This alloys have been widely used in automobile pistons. For this application thermal expansion coefficient is one important characteristics other than mechanical properties. In this project replacing Cobalt with Nickel to improve alloy thermal and mechanical properties in piston applications by different cobalt contents. Cobalt contents is 0, 0.15, 0.55 and 0.77 Wt%. Because of oxidation magnesium content decrease into 0.98, 0.74, 0.61 and 0.48 Wt%. Thermal expansion coefficient and UTS first increase and after 0.55 Cobalt Wt% show decrease But yield strength and hardness increase as cobalt content increase. Microscopic...