Influence of second phase precipitates on mechanical and in-vitro corrosion behaviour of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions
The present study investigates the mechanical and in-vitro corrosion behavior of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions. The optimization of the homogenization parameters has been carried out employing thermodynamic calculations and kinetic modeling. The model utilizes the inter-...
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KeAi Communications Co., Ltd.
2023-04-01
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| Series: | Journal of Magnesium and Alloys |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2213956722002833 |
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| author | Darothi Bairagi Partha Duley Manas Paliwal Sumantra Mandal |
| author_facet | Darothi Bairagi Partha Duley Manas Paliwal Sumantra Mandal |
| author_sort | Darothi Bairagi |
| collection | DOAJ |
| description | The present study investigates the mechanical and in-vitro corrosion behavior of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions. The optimization of the homogenization parameters has been carried out employing thermodynamic calculations and kinetic modeling. The model utilizes the inter-diffusivity of the solute elements and predicts that ∼6–24 h of homogenization at 633 K effectively redistributes the elements in the Mg matrix. Based on the insights obtained from the simulations, the as-cast Mg-4Zn-0.5Ca-0.8Mn alloy was subjected to homogenization heat treatment process for 6–24h. The microstructural study through optical microscopy and scanning electron microscopy (SEM) revealed that the interconnected network of second phase precipitates substantially dissolve within 24 h, implying adequate homogenization. Moreover, fine Mg-Zn based precipitates with varied morphology and phase fractions also evolved during homogenization treatment, as confirmed through SEM and transmission electron microscopy. In the 12 h homogenized specimen, the highest fraction of uniformly dispersed fine precipitates resulted in the highest strength (∼225 MPa). On the other hand, a substantial disruption in coarse precipitate network and lower aspect ratio of fine Mg-Zn precipitates led to the highest ductility (∼8%) in this specimen. In the 24 h homogenized specimen, the ductility reduced marginally owing to higher aspect ratio of fine precipitates. The immersion and electrochemical tests (viz., potentiodynamic polarization and electrochemical impedance spectroscopy) carried out in Hank's solution revealed that the 24 h homogenized specimen exhibits the best corrosion properties. The least fraction of Ca2Mg6Zn3 phase with maximum disruption in interconnectivity, in combination with a small fraction of fine equilibrium MgZn2 precipitates, resulted in suppression of localized corrosion in this specimen. This promotes the formation of the most stable and compact product layer over the specimen, resulting in the highest corrosion resistance. |
| first_indexed | 2024-03-13T07:42:34Z |
| format | Article |
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| issn | 2213-9567 |
| language | English |
| last_indexed | 2024-03-13T07:42:34Z |
| publishDate | 2023-04-01 |
| publisher | KeAi Communications Co., Ltd. |
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| series | Journal of Magnesium and Alloys |
| spelling | doaj.art-34052e3ca2a144308caf94596a32162b2023-06-03T04:22:06ZengKeAi Communications Co., Ltd.Journal of Magnesium and Alloys2213-95672023-04-0111413431366Influence of second phase precipitates on mechanical and in-vitro corrosion behaviour of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditionsDarothi Bairagi0Partha Duley1Manas Paliwal2Sumantra Mandal3Corresponding author.; Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, 721302, IndiaDepartment of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, 721302, IndiaDepartment of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, 721302, IndiaDepartment of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, 721302, IndiaThe present study investigates the mechanical and in-vitro corrosion behavior of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions. The optimization of the homogenization parameters has been carried out employing thermodynamic calculations and kinetic modeling. The model utilizes the inter-diffusivity of the solute elements and predicts that ∼6–24 h of homogenization at 633 K effectively redistributes the elements in the Mg matrix. Based on the insights obtained from the simulations, the as-cast Mg-4Zn-0.5Ca-0.8Mn alloy was subjected to homogenization heat treatment process for 6–24h. The microstructural study through optical microscopy and scanning electron microscopy (SEM) revealed that the interconnected network of second phase precipitates substantially dissolve within 24 h, implying adequate homogenization. Moreover, fine Mg-Zn based precipitates with varied morphology and phase fractions also evolved during homogenization treatment, as confirmed through SEM and transmission electron microscopy. In the 12 h homogenized specimen, the highest fraction of uniformly dispersed fine precipitates resulted in the highest strength (∼225 MPa). On the other hand, a substantial disruption in coarse precipitate network and lower aspect ratio of fine Mg-Zn precipitates led to the highest ductility (∼8%) in this specimen. In the 24 h homogenized specimen, the ductility reduced marginally owing to higher aspect ratio of fine precipitates. The immersion and electrochemical tests (viz., potentiodynamic polarization and electrochemical impedance spectroscopy) carried out in Hank's solution revealed that the 24 h homogenized specimen exhibits the best corrosion properties. The least fraction of Ca2Mg6Zn3 phase with maximum disruption in interconnectivity, in combination with a small fraction of fine equilibrium MgZn2 precipitates, resulted in suppression of localized corrosion in this specimen. This promotes the formation of the most stable and compact product layer over the specimen, resulting in the highest corrosion resistance.http://www.sciencedirect.com/science/article/pii/S2213956722002833Mg alloyThermodynamic-kinetic calculationHomogenizationEISPassive film |
| spellingShingle | Darothi Bairagi Partha Duley Manas Paliwal Sumantra Mandal Influence of second phase precipitates on mechanical and in-vitro corrosion behaviour of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions Journal of Magnesium and Alloys Mg alloy Thermodynamic-kinetic calculation Homogenization EIS Passive film |
| title | Influence of second phase precipitates on mechanical and in-vitro corrosion behaviour of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions |
| title_full | Influence of second phase precipitates on mechanical and in-vitro corrosion behaviour of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions |
| title_fullStr | Influence of second phase precipitates on mechanical and in-vitro corrosion behaviour of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions |
| title_full_unstemmed | Influence of second phase precipitates on mechanical and in-vitro corrosion behaviour of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions |
| title_short | Influence of second phase precipitates on mechanical and in-vitro corrosion behaviour of Mg-4Zn-0.5Ca-0.8Mn alloy in optimum homogenized conditions |
| title_sort | influence of second phase precipitates on mechanical and in vitro corrosion behaviour of mg 4zn 0 5ca 0 8mn alloy in optimum homogenized conditions |
| topic | Mg alloy Thermodynamic-kinetic calculation Homogenization EIS Passive film |
| url | http://www.sciencedirect.com/science/article/pii/S2213956722002833 |
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