Fabrication and anodising of aluminium matrix composite made from flaky aluminium powder and short fibre Saffil™ alumina

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dc.contributor.authorDerman, Mohd Nazree
dc.date.accessioned2014-11-03T02:26:54Z
dc.date.available2014-11-03T02:26:54Z
dc.date.issued2006
dc.descriptionPhDen_US
dc.description.abstractA study of fabrication and anodising on aluminium matrix composites (AMC) made from flaky aluminium powder and short fibre alumina Saffil™ was carried out. AMC fabrication by powder metallurgy methods (PM) using dry mixing and sintered in nitrogen was studied to determine the best sintering time and optimum percentage of Saffil™ alumina short fibres content. Sulphuric acid anodising process was performed and the objective is to obtain suitable parameters of sulphuric acid concentration, anodising voltage and anodising time. Characterisation on AMC included anodised also involved corrosion and wear test. The optimum Saffil™ alumina short fibre contents (0 to wt 25%) was determined by microstructure, density and porosity test, tensile strength, microhardness test, X-ray diffraction (XRD) analysis and coefficient of thermal expansion (CTE) analysis. The study of anodising process was carried out with various sulphuric acid concentrations (from 0 to 20% volume), anodising voltage (10 V to 20 V) and anodising time (from 0 to 60 minutes) at room temperature. Corrosion tests was also done in 3.5 wt% sodium chloride (NaCl) solution using electrochemical polarisation measurement based on ASTM G5 (1999), whereas pin-on-disk test was used for wear testing. From the research, AMC from flaky Al powders and Saffil™ alumina short fibre was successfully produced with good properties using dry mixing method and sintered in nitrogen atmosphere for 7 hours. AMC reinforced with 15 wt% Saffil™ alumina short fibre was selected because it showed optimum properties such as relatively uniform distribution of fibres in Al matrix, relatively low density, 2.61 g cm-3 and low porosity 1.33%. The tensile strength value for AMC reinforced with 15 wt% was 105.04 MPa, elastic modulus 8.38 GPa and microhardness HVN 84.02, CTE 16.41 x 10-6 K-1 and small linear changes with no new phases as shown by XRD results. Anodising voltage of 15 V and 15 vol% H2SO4 in anodising time of 60 minutes were suitable parameters for sulphuric acid anodising of this AMC. The anodising can reduce corrosion reaction rate on Al and AMC with decreasing corrosion current density. Anodising also reduced 59% and 13% wear coefficient of Al and AMC, respectively. Generally, the results showed that good properties of AMC can be fabricated from flaky Al powders reinforced with Saffil alumina shorts fibre by PM methods. AMC reinforced with 15% alumina shorts fibre Saffil™ was the best AMC. The AMC showed higher corrosion rate but lower wear rate compared to the Al samples. From the research, it was found that H2SO4 anodising was able to give good coating to AMC. The anodised AMC samples showed better corrosion resistance and wear resistance.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/308
dc.language.isoenen_US
dc.subjectMaterials and Mineral Resources Engineeringen_US
dc.subjectAluminium matrix compositeen_US
dc.subjectFlaky aluminium powderen_US
dc.subjectSaffil™ aluminaen_US
dc.titleFabrication and anodising of aluminium matrix composite made from flaky aluminium powder and short fibre Saffil™ aluminaen_US
dc.typeThesisen_US
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