The Influence of Yttrium Addition on Strength and Corrosion Resistance of Mg-Y Binary Fabricated from Mg Anode Source

• Main Author: Ardiyana, Herdi
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/36838
• Institution: Institut Teknologi Bandung

This final project research shows the effect of adding 2%, 4%, and 6% ytrium weight to the mechanical properties and corrosion resistance of magnesium yittrium alloys. Alloy Mg-Y is made by the melting method in a controlled atmosphere of CO2 + HFC134a and temperature (700-770)oC. Characterization and testing of ingots such as metallography, XRD, SEM EDS, tensile test, hardness test, immersion test, and polarization test were carried out. There is a grain refinement due to addition of yttrium content which increases its mechanical properties. In addition, other reinforcement mechanisms occur such as solid solutions along with the addition of yttrium. The results of tensile tests revealed that there is an increasement of mechanical properties due to addition of yittrium content. Beside of that, the hardness test also revealed an increasement of hardness due to addition of yittrium content. Furthermore, the MgY alloy was immersed in Ringer's solution to see corrosion resistance and the corrosion rates was obtained for Mg2Y, Mg4Y, and Mg6Y alloys are 1.18 mmpy, 5.48 mmpy, and 104.48 mmpy respectively. Optimum corrosion resistance for Mg2Y is obtained. The mechanism of corrosion of the binary Mg-Y includes microgalvanic and pitting corrosion. This can be confirmed from macrostructure results which indicate that the mode of corrosion that occurs is pitting. Whereas microgalvanic corrosion occurs due to the presence of secondary phases characterized by XRD. From the results of SEM EDS, it shows that there is an area that Yttrium rich zone at the grain boundary and in some areas in the middle of the grain which is scattered randomly. This phase distribution increases the corrosion rate experienced by Mg-Y itself or is often referred to as microgalvanic corrosion mode followed by pitting corrosion.