Type

PhD Thesis

Authors

Sumsun Naher

Subjects

Engineering

Topics
metal castings room temperature design and construction computer simulations metallic composites electronic engineering high temperature metal matrix composites

Examination of the stir-casting method to produce Al-SiC composites (2004)

Abstract This work examined the influence of processing parameters on the production of Al-SiC metal matrix composites (MMC) by batch compocasting process. Processing parameters investigated includes tirring speed, stirring time, stirrer geometry, stirrer position , metal fluid temperature (viscosity). Room temperature (25°C) visual simulations, computer simulations and validation Al-SiC MMC production tests were performed. In the visual and computer simulations, water an d g ly c e ro l/water were used to represent liquid an d semi-solid a lum in ium respectively. The effects of viscosities of 1, 300, 500, 800 and 1000 mPas and stirrin g speeds of 50, 100, 150, 200, 250 and 300 rpm were investigated. A 10 vol. % reinforced SiC particulate , similar to that used in the aluminium MMC’s, was used in the visualisation and computational tests. The visualisation tests were carried out in a transparent glass beaker. The computational simulation was performed with Fluent(CFD software) an d an ad d on package MixSim. This consisted of a 2D axisym metric multip h a se time dependent simulation of the production routeusing an Eulerian (granular) model. The dependence of particle dispersion times, settling timesand vortex height on stirring geometry and stirrer speed was found. A blade angle of 60 degrees was found better for the flat blade stirrer, to obtain uniform particulate dispersions quickly. From the setestsas tirrin g speed of 150 rpm for water-SiC an d 300 rpm for the glycerol/water-S iC sy stem were found to be necessary in order to obtain a uniformd is tribution of the SiC. A viscosity increase from 1 mPas (for liquid metal) to 300 m Pas (for semi-solid metal) was found to have a tremendous effect on the SiC dispersion and settling times. However, a further increase from 300 mPas to 1000 mPashad negligible effect on this time. A significant part of the work consisted of the design, construction and validation of a specialised quick quench compocaster for this high temperature processing method. This machine consisted of a stirrer with four 60 degree angled flat blades and a cruciblein a resistance heated furnace chamber. An actuator was integrated to this rig to enable quick quenching of the processed mixture. This device was used to produce Al-SiC composites. Generally, good agreement was found between the visualisation, computational and validation experimental results.
Collections Ireland -> Dublin City University -> Thesis Type = Doctoral Thesis
Ireland -> Dublin City University -> Publication Type = Thesis
Ireland -> Dublin City University -> DCU Faculties and Centres = DCU Faculties and Schools
Ireland -> Dublin City University -> Subject = Engineering: Electronic engineering
Ireland -> Dublin City University -> DCU Faculties and Centres = DCU Faculties and Schools: Faculty of Engineering and Computing: School of Mechanical and Manufacturing Engineering
Ireland -> Dublin City University -> Status = Unpublished
Ireland -> Dublin City University -> DCU Faculties and Centres = DCU Faculties and Schools: Faculty of Engineering and Computing
Ireland -> Dublin City University -> Subject = Engineering

Full list of authors on original publication

Sumsun Naher

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Sumsun Naher
Dublin City University
Total Publications: 56