Effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications

Some of magnesium alloys have poor corrosion resistance in ambient air or aqueous environment due to their electrochemically active state. Different surface coating techniques, alloying and heat treatment are the ways to enhance the corrosion performance of magnesium alloys. The goal of this researc...

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Main Author:	Hasbullah, Nurul Ai'zzah
Format:	Thesis
Language:	English
Published:	2015
Subjects:	TJ Mechanical engineering and machinery
Online Access:	http://eprints.utm.my/id/eprint/53637/1/NurulAiZzahHasbullahMFKM2015.pdf
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spelling	my-utm-ep.536372020-08-23T08:54:44Z Effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications 2015-09 Hasbullah, Nurul Ai'zzah TJ Mechanical engineering and machinery Some of magnesium alloys have poor corrosion resistance in ambient air or aqueous environment due to their electrochemically active state. Different surface coating techniques, alloying and heat treatment are the ways to enhance the corrosion performance of magnesium alloys. The goal of this research is to study the characteristic and corrosion behaviour of quaternary Mg-Zn-RE-Ca alloys due to thermal treatment. The effects of two types of heat treatments, T4 (solution treatment) and T6 (aging treatment) on corrosion behaviour of quaternary Mg-2.2Zn- 3.7RE-0.5Ca alloys were studied. Microstructural evaluations were characterized using optical microscope and scanning electron microscope (SEM). The compositions of the material were determined by X-ray diffractometer (XRD) and energy dispersive X-ray spectrometer (EDS). The corrosion features were examined in-vitro by potentiodynamic polarization, pH variation and immersion test in Hank?s solution at room temperature (27°) with pH 7.4. It was found that a-Mg matrix, eutectic phase Mg12RE and Mg29Zn25RE with intermetallic IM1 precipitates formed in the quaternary Mg-Zn-RE-Ca system. T4 treatment produced supersaturated a-Mg while the secondary phases were mostly dissolved in the matrix. The lamellar structure which composed of IM1 precipitated after T6-treated were detected along the grain boundaries. The hardness of quaternary magnesium based alloy decreased significantly after T4 treatment and increased after T6 treatment. The pH value for T6 treatment shows the lowest after 96 hours immersion in Hank?s solution. Electrochemical measurement shows that T4 and T6 treatments increased the corrosion resistance of the quaternary magnesium alloy. It was found that the corrosion products consists mainly pure magnesium, magnesium hydroxide (Mg(OH)2), and hydroxyapatite (HA). 2015-09 Thesis http://eprints.utm.my/id/eprint/53637/ http://eprints.utm.my/id/eprint/53637/1/NurulAiZzahHasbullahMFKM2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:84641 masters Universiti Teknologi Malaysia, Faculty of Mechanical Engineering Faculty of Mechanical Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TJ Mechanical engineering and machinery
spellingShingle	TJ Mechanical engineering and machinery Hasbullah, Nurul Ai'zzah Effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications
description	Some of magnesium alloys have poor corrosion resistance in ambient air or aqueous environment due to their electrochemically active state. Different surface coating techniques, alloying and heat treatment are the ways to enhance the corrosion performance of magnesium alloys. The goal of this research is to study the characteristic and corrosion behaviour of quaternary Mg-Zn-RE-Ca alloys due to thermal treatment. The effects of two types of heat treatments, T4 (solution treatment) and T6 (aging treatment) on corrosion behaviour of quaternary Mg-2.2Zn- 3.7RE-0.5Ca alloys were studied. Microstructural evaluations were characterized using optical microscope and scanning electron microscope (SEM). The compositions of the material were determined by X-ray diffractometer (XRD) and energy dispersive X-ray spectrometer (EDS). The corrosion features were examined in-vitro by potentiodynamic polarization, pH variation and immersion test in Hank?s solution at room temperature (27°) with pH 7.4. It was found that a-Mg matrix, eutectic phase Mg12RE and Mg29Zn25RE with intermetallic IM1 precipitates formed in the quaternary Mg-Zn-RE-Ca system. T4 treatment produced supersaturated a-Mg while the secondary phases were mostly dissolved in the matrix. The lamellar structure which composed of IM1 precipitated after T6-treated were detected along the grain boundaries. The hardness of quaternary magnesium based alloy decreased significantly after T4 treatment and increased after T6 treatment. The pH value for T6 treatment shows the lowest after 96 hours immersion in Hank?s solution. Electrochemical measurement shows that T4 and T6 treatments increased the corrosion resistance of the quaternary magnesium alloy. It was found that the corrosion products consists mainly pure magnesium, magnesium hydroxide (Mg(OH)2), and hydroxyapatite (HA).
format	Thesis
qualification_level	Master's degree
author	Hasbullah, Nurul Ai'zzah
author_facet	Hasbullah, Nurul Ai'zzah
author_sort	Hasbullah, Nurul Ai'zzah
title	Effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications
title_short	Effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications
title_full	Effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications
title_fullStr	Effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications
title_full_unstemmed	Effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications
title_sort	effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications
granting_institution	Universiti Teknologi Malaysia, Faculty of Mechanical Engineering
granting_department	Faculty of Mechanical Engineering
publishDate	2015
url	http://eprints.utm.my/id/eprint/53637/1/NurulAiZzahHasbullahMFKM2015.pdf
_version_	1747817600401801216

Effect of heat treatment on the microstructures and corrosion behaviour of quaternary mg-2.2zn-3.7re-0.5ca alloys for biomedical applications

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