Fazimah Mat Noor

Potassium Bromide as Space Holder for Titanium Foam Preparation

Titanium (Ti) alloy foam was prepared by using potassium bromide (KBr) as space holder with percentage between 20 to 40 wt.%. In this work, the potential of KBr as a new space holder was determined. The Ti alloy powder and space holder were first manually mixed before being compacted using hydraulic hand press. The green compacts were then sintered at temperature of 1160°C, 1200°C and 1240°C in a tube furnace. The microstructure of the Ti alloy foams were observed by Scanning Electron Microscope (SEM). It was revealed that the porosity content in the Ti foam was in the range of 16% to 31% and density in the range of 1.5 g/cm3 to 2.6 g/cm3. Moreover, the pore size of the titanium alloy foam is in the range of 187μm to 303μm. Although the sintering temperatures were found incapable of promoting overall densification to the Ti alloy foam, 1200°C was denoted to be the maximal temperature for promoting maximal porosity to the Ti alloy foam. Nonetheless, KBr was proven to be suitable as space holder for Ti foam preparation as referred to its stability and insolubility in the Ti alloy.

Physical and Mechanical Characteristics of Porous SS316L for Biomedical Implant

Porous materials with open and interconnected pores are very interesting for biomedical applications as it provides a good base for the formation of bone ingrowth naturally. Besides, it also allows for body fluid transportation through the interconnected network. Therefore, in this work, foam replication method has been used to produce porous SS316L. The SS316L slurries were prepared by ball milling and mechanical stirring method. The polyurethane (PU) foam has been used as a sacrificial template. Sintering process was carried in a high vacuum furnace at 1200°C, 1250°C and 1300°C. The overall results show that increasing the sintering temperature from 1200°C to 1300°C and the using of different slurry mixing methods did not significantly affect the physical and mechanical properties of the porous SS316L produced. The density, porosity percentage and compression strength found for this porous SS316L were in the range of 1.35g/cm3-3g/cm3, 62% - 83%, and 30.6MPa-79MPa respectively. The SEM images also show that the microstructure of this porous SS316L mostly consisted of open and interconnected pores. Therefore, these results are very promising for biomedical implant application.

Effect of triggering angles on the crushing mechanisms of hybrid woven kenaf/aluminum hollow cylinders

This paper presents the effect of triggering angles constructed on the top of hybrid woven kenaf/aluminium hollow cylinders on the energy absorption performances. The crushing performances of aluminium tubes can be found widely in open literature. However, lack number of work on the hybridizing the aluminium tubes with woven kenaf fibre is found. Woven kenaf mats are produced and bathed with polymeric resin before they are wrapped around the aluminium tubes twice. Different fibre orientations, +-θ° are used where θ = 0, 15, 30 and 45. Once the hybrid composite hardened, one of their end are chamfered using different angles of 0o, 30o, 45o and 60o. The tubes are quasi-statically compressed in order to obtain their force-displacement responses and crashworthiness parameters are extracted and discussed with the relation of fibre orientations and chamfering angles. It is found that the chamfering angles are only affected the force-displacement curves during the first stage of elastic deformation whereas there is no obvious effect in the second stage. However, varying the fibre orientations are slightly increased the force-displacement curves especially when the fibre is orientated with 30o. Based on the fracture mechanism observations, most of composite experienced large fragmentation indicating that the composites absorbed the crushing energy ineffectively.

Production of Stainless Steel 316L Foam with Different Solid Loading

Stainless steel foam has been used for various applications due to their advantages over other materials such as high corrosion resistance, easily availability, and low-cost as well as good mechanical properties. In this work, stainless foam was produced by using foam replication method with different solid loading of SS316L i.e 55 wt%, 60 wt%, 65 wt% and 70 wt% SS316L. The samples were sintered in a vacuum furnace at 1250°C. The sample microstructure was characterized by using scanning electron microscope (SEM) while the elemental component was analyzed by using Energy Dispersive X-ray (EDX). The Archimedes test has been conducted to determine the samples density and porosity. It was found that the best sample is SS316L foam with 65 wt% solid loading with the density and porosity of 1.85 g/cm3 and 76.84% respectively which are similar to the human bone. The sample also has open and interconnected pores.

The Formation of Cobalt Chromium Molybdenum (CoCrMo) Foams Fabricated by Slurry Method

Cobalt Chromium Molybdenum (CoCrMo) is a metal that are widely used in the biomedical field of orthopedic applications. CoCrMo foam was developed in the form of a porous structure where it has a high porosity on the surface with the different pore sizes and shapes. This research is intended to produce CoCrMo foam by using slurry method and to study the effect of composition and sintering temperature on the metal foams. The slurry of CoCrMo was prepared by mixing the binder materials of Methylcellulose (CMC), Polyethylene Glycol (PEG) and distilled water for an hour. Followed by mixing and stirring the CoCrMo powder for another 1 hour until it becomes slurries. Polyurethane (PU) foam was then impregnated into the slurry and dried for a day in the oven with 60 °C. Sintering process is carried out at temperature of 1000 °C, 1100 °C and 1200 °C using a tube furnace. Then sample of CoCrMo foam was going through a shrinkage measurement, microstructure analysis by using Scanning Electron Microscope (SEM), analysis of element by using Energy Diffraction X-ray (EDX) and also the density and porosity test by using Archimedes method. The sample with the composition of 65wt% was the best result in this experiment. While sintering temperature of 1200 °C produced the highest number of porosities. The shrinkage percentage is from 2.67% to 14.13%. The density obtained is in between 1.538 g/cm3 and 2.706 g/cm3 while the percentage of porosity is from 50.284% to 78.934%. The average pore size is in the range of 249.63μm to 445.38μm. The best sintering temperature and composition to produced high porosity were on 1200 °C and 65wt%.

Development and Characterization of SS316L Foam Prepared by Powder Metallurgy Route

Open cell foams, made on the basis of polyurethane foams replication method are well known and had been widely used since decades. The advantage of the network-like metal foams is it exhibits a natural bone-like structure which enables ingrowth of bone cells and blood vessels. The aim of the present study is to develop SS316L foam with an open cell structure by using powder metallurgy routes via foam replication method. The SS316L slurry was produced by mixing SS316L powder with Polyethylene Glycol (PEG), Methylcellulose (CMC) and distilled water. The composition of the SS316L powder in the slurry was varied from 40 to 60 wt. %. Then, polymeric foam template was impregnated in SS316L slurry and dried at room temperature. Sintering was carried out in a high temperature vacuum furnace at 1300°C. The microstructure of the SS316L foam produced was observed by Scanning Electron Microscope (SEM) and the elemental analysis was carried by Energy Dispersive X-ray (EDX). It was found that pore size are within 200-400μm and the average pore size is 293μ. The detected elements in the SS316L foam were C, Al, Ca, O, Cr, Fe, Mo, Ni and Si.