Foam replicated porous 316l stainless steel based on taguchi method for biomedical applications

Mat Noor, Fazimah (2018) Foam replicated porous 316l stainless steel based on taguchi method for biomedical applications. Doctoral thesis, Universiti Teknologi Malaysia.

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Abstract

The mismatch between elastic modulus of metal implants and bones which is also known as stress shielding, remains an unresolved issue. Porous metals are one of the most effective ways of reducing stiffness mismatches and achieving stable longterm fixation via full bone in-growth. In this work, porous SS316L is produced using the foam replication technique. The samples were each produced with different compositions of SS316L powders and sintered at various sintering parameters including the sintering temperature, sintering time, heating rate and cooling rate. Scanning electron microscopy (SEM) was used to characterise the microstructure while a compression test was used to determine the mechanical properties of the samples. The physical properties including porosity and density were measured according to the Archimedes principles. The biocompatibility test showed that the porous SS316L produced, exhibited no cytotoxicity reactivity. Furthermore, the optimisations of the sintering parameters were performed using the Taguchi method. The optimised porosity of porous SS316L prepared by ball milling method was 85.44% and achieved using sintering time of 60 minutes, sintering temperature of 1200C, heating rate of 1C/min, SS316L composition of 60 wt% and cooling rate of 1C/min. Whereas, for samples prepared by mechanical stirring method, the optimum porosity was 79.46% and occurred for the samples sintered within 60 minutes at 1200C of sintering temperature, with the cooling and heating rates of 1C/min and 2C/min respectively, and prepared with 70 wt% of SS316L composition. In addition, porous SS316L prepared by ball milling method with modulus of elasticity of 0.08 GPa was obtained by using optimum sintering temperature of 1250C, sintering time of 60 minutes, heating rate of 2C/min, SS316L composition of 65 wt% and cooling rate of 1C/min. Whereas, the modulus of elasticity of 0.05 GPa for porous SS316L prepared by mechanical stirring method was obtained by using the optimum cooling rate of 5C/min, sintering temperature of 1200C, sintering time of 120 minutes, SS316L composition of 70 wt% and heating rate of 0.5C/min respectively. Following optimisation, the porous SS316L produced was found to have attractive mechanical and physical properties much like human bone. Notwithstanding, this included interconnected and open porosity in the range of 79.46 to 85.44 %, density in the range of 1.53-1.76 g/cm , pore size in the range of 247–470 µm, modulus of elasticity in the range of 0.05-0.08 GPa, yield strength in the range of 0.52–0.82 MPa and compression strength in the range of 35.87-64.43 MPa. 3

Item Type: Thesis (Doctoral)
Subjects: Q Science > QC Physics > QC501-766 Electricity and magnetism
Depositing User: Mrs. Sabarina Che Mat
Date Deposited: 30 Aug 2021 03:05
Last Modified: 30 Aug 2021 03:05
URI: http://eprints.uthm.edu.my/id/eprint/692

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