The effect of Zn alloying on the mechanical properties and corrosion resistance of as-cast Mg-Zn alloys fabricated from sacrificial Mg anode
Magnesium alloys are promising candidates for the application of implant material that can be degraded in the human body. Several studies have been conducted to examine the properties of magnesium alloys, especially the binary alloy Mg-Zn. But there are still problems regarding the optimal compositi...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/36299 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Magnesium alloys are promising candidates for the application of implant material that can be degraded in the human body. Several studies have been conducted to examine the properties of magnesium alloys, especially the binary alloy Mg-Zn. But there are still problems regarding the optimal composition to obtain mechanical and corrosion properties that are suitable as biodegradable implants. In this study we will study the effect of Zn elements on the mechanical properties and corrosion resistance of casting Mg-Zn binary alloys. The Zn alloy studied had a content of 1wt%, 3wt%, and 5wt%. All alloys are fabricated using magnesium anode containing Mn elements and Zn anode with in-house casting techniques accompanied by CO2 + HCF134a protective gas at 700-720oC. The chemical composition of the alloy is characterized by atomic absorption spectroscopy (AAS), electron probe micro-analyzer (EPMA), and SEM-EDS. Microstructure observation was conducted with optical microscopy and identification of phases formed was carried out with XRD. Furthermore, tensile testing was carried out to see the mechanical properties of alloys. Immersion testing, measurements of hydrogen evolution volume and polarization corrosion tests to determine the corrosion properties of alloys. The results of this study indicate that the combination with Zn will increase the toughness of the alloy and increase the corrosion resistance of magnesium except for magnesium Mg-1Zn because there are Cu impurities which form brittle phase on the alloy and increase the corrosion rate. The results of the immersion test and measurements of hydrogen evolution volume showed that Mg-3Zn had better corrosion resistance, whereas the results of tafel polarization testing showed Mg-5Zn had better corrosion resistance. The difference in results obtained from corrosion resistance testing is caused by corrosion of magnesium alloys that are not uniform. The addition of Zn to 5wt% will also effectively refine magnesium grains.
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