Microstructure and properties of sintered Co-Cr-Mo alloy powder under different processing conditions

Co-Cr-Mo (ASTM F-75) alloy is one of the most important metallic biomaterials that are commonly used for surgical implant due to its mechanical properties, good wear resistance and biocompatibility. This study has focused on the effect of sintering time and sintering temperature on the microstruc...

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Main Author:	Zuraidawani, Che Daud
Format:	Thesis
Language:	English
Subjects:	Biomedical materials Alloys Biomaterials
Online Access:	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/63438/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/63438/2/Full%20text.pdf
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spelling	my-unimap-634382019-11-29T03:33:36Z Microstructure and properties of sintered Co-Cr-Mo alloy powder under different processing conditions Zuraidawani, Che Daud Prof. Dr. Shamsul Baharin Jamaludin Co-Cr-Mo (ASTM F-75) alloy is one of the most important metallic biomaterials that are commonly used for surgical implant due to its mechanical properties, good wear resistance and biocompatibility. This study has focused on the effect of sintering time and sintering temperature on the microstructure development and properties of sintered Co-Cr-Mo alloy powder, sintering mechanism and activation energy, and corrosion behaviour. In the fabrication of PM Co-Cr-Mo alloy, five weight percentages (wt. %), 1.0, 1.5, 2.0, 2.5 and 3.0 of binder (stearic acid) were studied to determine the optimum amount of binder content based on the results of linear shrinkage, bulk density, apparent porosity and Vickers microhardness of the sintered samples. Then the Co-Cr-Mo alloy powder were blended with the selected amount of optimum binder (2wt. % of stearic acid) using a rotation mill at 16SRPM for 30 minutes, uniaxially pressing at SOOMPa and sintering in a furnace at three different sintering temperatures (12S0°C, 1300°C and 13S0°C) for five sintering times (30, 60, 90, 120 and 150 minutes) in argon atmosphere. The characterisation on sintered samples were carried out based on microstructure, grain size, bulk density and apparent porosity, Vickers microhardness test and followed by compressive strength. The study of sintering mechanism was carried out in order to determine the activation energy of Co-CrMo alloy. The corrosion behaviour of selected samples was analysed based on the minimum value of compressive strength. For corrosion test, the selected samples were immersed in simulated body fluid, 0.9% sodium chloride (NaCt) solution at 37°C for 90 days. From this study, the values of bulk density and grain size increased with increasin~ sintering temperature and sintering time. The bulk density values are in the range 7.04g/cm to 7.21 g/cm3 , 7.16 g/cm3 to 7.28 g/cm3 and 7.45 g/cm3 to 7.54 g/cm3 for sintering temperature of 1250°C, 1300°C and 1350°C, respectively for five sintering times. Meanwhile, the grain sizes for five sintering times are 25.6~m to 37.7~m, 36.6~m to 44.5~m and 80.4~m to 89.9~m respectively for the three sintering temperatures. However, opposite results were obtained for apparent porosity, hardness and compressive strength. The samples sintered at 13S0°C have the highest values of hardness (303HV -294HV) and compressive strength (329MPa-206MPa) for 30 to 150 minutes of sintering times. Based on the fracture mode, all samples show the fracture with a shear mode and occurred close to an angle of 45° from the compressive axis. The samples sintered at 12S0°C and 1300°C exhibited smooth transgranular fracture mode. Meanwhile, the step-like transgranular fracture mode was observed in the samples sintered at 1350°C. The results of corrosion test showed that sample sintered at 1300°C gives the highest value of corrosion rate (0.07Smpy) meanwhile sample sintered at 1350°C has the lowest corrosion rate (0.006mpy). From this study, the samples sintered at 13S0°C with 120 minutes of sintering times showed the compressive strength close to the bone strength and better corrosion properties. Universiti Malaysia Perlis (UniMAP) 2011 Thesis en http://dspace.unimap.edu.my:80/xmlui/handle/123456789/63438 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/63438/1/Page%201-24.pdf 53c6bd86ea0355fd38566e084f36acc7 http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/63438/2/Full%20text.pdf dac79df901d5f273d2dc4957f9ec89ff http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/63438/3/license.txt 8a4605be74aa9ea9d79846c1fba20a33 Biomedical materials Alloys Implants, Artificial -- Materials Biomaterials School of Materials Engineering
institution	Universiti Malaysia Perlis
collection	UniMAP Institutional Repository
language	English
advisor	Prof. Dr. Shamsul Baharin Jamaludin
topic	Biomedical materials Alloys Biomedical materials Biomaterials
spellingShingle	Biomedical materials Alloys Biomedical materials Biomaterials Zuraidawani, Che Daud Microstructure and properties of sintered Co-Cr-Mo alloy powder under different processing conditions
description	Co-Cr-Mo (ASTM F-75) alloy is one of the most important metallic biomaterials that are commonly used for surgical implant due to its mechanical properties, good wear resistance and biocompatibility. This study has focused on the effect of sintering time and sintering temperature on the microstructure development and properties of sintered Co-Cr-Mo alloy powder, sintering mechanism and activation energy, and corrosion behaviour. In the fabrication of PM Co-Cr-Mo alloy, five weight percentages (wt. %), 1.0, 1.5, 2.0, 2.5 and 3.0 of binder (stearic acid) were studied to determine the optimum amount of binder content based on the results of linear shrinkage, bulk density, apparent porosity and Vickers microhardness of the sintered samples. Then the Co-Cr-Mo alloy powder were blended with the selected amount of optimum binder (2wt. % of stearic acid) using a rotation mill at 16SRPM for 30 minutes, uniaxially pressing at SOOMPa and sintering in a furnace at three different sintering temperatures (12S0°C, 1300°C and 13S0°C) for five sintering times (30, 60, 90, 120 and 150 minutes) in argon atmosphere. The characterisation on sintered samples were carried out based on microstructure, grain size, bulk density and apparent porosity, Vickers microhardness test and followed by compressive strength. The study of sintering mechanism was carried out in order to determine the activation energy of Co-CrMo alloy. The corrosion behaviour of selected samples was analysed based on the minimum value of compressive strength. For corrosion test, the selected samples were immersed in simulated body fluid, 0.9% sodium chloride (NaCt) solution at 37°C for 90 days. From this study, the values of bulk density and grain size increased with increasin~ sintering temperature and sintering time. The bulk density values are in the range 7.04g/cm to 7.21 g/cm3 , 7.16 g/cm3 to 7.28 g/cm3 and 7.45 g/cm3 to 7.54 g/cm3 for sintering temperature of 1250°C, 1300°C and 1350°C, respectively for five sintering times. Meanwhile, the grain sizes for five sintering times are 25.6~m to 37.7~m, 36.6~m to 44.5~m and 80.4~m to 89.9~m respectively for the three sintering temperatures. However, opposite results were obtained for apparent porosity, hardness and compressive strength. The samples sintered at 13S0°C have the highest values of hardness (303HV -294HV) and compressive strength (329MPa-206MPa) for 30 to 150 minutes of sintering times. Based on the fracture mode, all samples show the fracture with a shear mode and occurred close to an angle of 45° from the compressive axis. The samples sintered at 12S0°C and 1300°C exhibited smooth transgranular fracture mode. Meanwhile, the step-like transgranular fracture mode was observed in the samples sintered at 1350°C. The results of corrosion test showed that sample sintered at 1300°C gives the highest value of corrosion rate (0.07Smpy) meanwhile sample sintered at 1350°C has the lowest corrosion rate (0.006mpy). From this study, the samples sintered at 13S0°C with 120 minutes of sintering times showed the compressive strength close to the bone strength and better corrosion properties.
format	Thesis
author	Zuraidawani, Che Daud
author_facet	Zuraidawani, Che Daud
author_sort	Zuraidawani, Che Daud
title	Microstructure and properties of sintered Co-Cr-Mo alloy powder under different processing conditions
title_short	Microstructure and properties of sintered Co-Cr-Mo alloy powder under different processing conditions
title_full	Microstructure and properties of sintered Co-Cr-Mo alloy powder under different processing conditions
title_fullStr	Microstructure and properties of sintered Co-Cr-Mo alloy powder under different processing conditions
title_full_unstemmed	Microstructure and properties of sintered Co-Cr-Mo alloy powder under different processing conditions
title_sort	microstructure and properties of sintered co-cr-mo alloy powder under different processing conditions
granting_institution	Universiti Malaysia Perlis (UniMAP)
granting_department	School of Materials Engineering
url	http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/63438/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/63438/2/Full%20text.pdf
_version_	1747836857700319232

Microstructure and properties of sintered Co-Cr-Mo alloy powder under different processing conditions

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