EFFECT OF INOCULANTS ON THE STRUCTURE AND MECHANICAL PROPERTIES OF AL-12.5%SI EUTECTIC ALLOYS

AUTHOR: NWAMBU, CHIDUME NNAMDI

DEPARTMENT: METALLURGICAL AND MATERIALS ENGINEERING

AFFILIATION: NNAMDI AZIKIWE UNIVERSITY, AWKA

This research work examined the effects of inoculants on structure and mechanical properties of aluminium-12.5%silicon alloys. Manganese, cobalt and molybdenum were used as modifying elements while sodium fluoride and sodium chloride were used as refining elements during this experiment. These inoculants were added as micro additive at various compositions to the percentage of iron present in the master alloys (1% of Fe: 1, 2, 3, 4% of modifying elements and 1/3NaF + 2/3NaCl refining elements). These alloys were produced by melting a calculated mass of pure aluminium and silicon, and subsequently micro additives (inoculants) were added to the melt, which was cast into rod-like ingots from which mechanical tests and microstructure examination specimens were produced and used for conducting the tests. Tensile strength was determined using the TUE-C- 100 Model universal tensile machine, impact strength was determined using Samuel Denison, Model LS10 2DE impact testing machine, hardness was determined using the Vickers test 18506 model DIN 51224 and 150/V716 while chemical composition analysis was conducted using chemical analyser and microstructure examination was done using metallurgical microscope. The results showed that the hardness and ultimate tensile strength improved as the iron content in the alloy was reduced, especially for those with cobalt addition while the micro-structural result confirmed that silicon particles were homogenously distributed in the alloy. The analysis of variance was used to identify the interactions between the significant and non-significant variables that affected the process.

TO VIEW THE FULL CONTENT OF THIS DOCUMENT, PLEASE VISIT THE UNIZIK LIBRARY WEBSITE USING THIS LINK, http://naulibrary.org/dglibrary/admin/book_directory/Thesis/11680.pdf

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