The Effect of Cobalt on Thermal Expansion and Metallurgical Properties of LM13 Alloy

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Ejlali, Saeed | 2018

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 50641 (07)
University: Sharif University of Technology
Department: Materials Science and Engineering
Advisor(s): Varahram, Naser
Abstract:
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 studies show that MgSi2 precipitation and Fe-contain intermetallic compounds decrease and Cu-contain intermetallic compounds increase is the reason of results. Most important result of this project is replacing Cobalt with Nickel with Cobalt content between 0.77 to 1 Wt% can decrease production costs and improve properties of piston that results customer satisfaction
Keywords:
Aluminum Alloy ; Piston ; Thermal Expansion ; Heat Resistance ; Replacing Cobalt with Nickel

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