The central objective of this research was to assess the effects of temperature and particle size on the spark plasma sintering (SPS) response of two prealloyed aluminium powders atomised from wrought alloys AA 2024 and AA 7075. A SPS temperature of 400uC was found to yield fully dense specimens of both alloys with hardness values that were comparable to the starting wrought ingot materials. Such samples also exhibited appreciably lower concentrations of residual oxygen and hydrogen when compared to those present in the raw powders. Degassing experiments completed through thermogravimetric analyser (TGA)-gas chromatography (GC)-mass spectrometry (MS) indicated that the release of CO 2 and adsorbed/chemisorbed H 2 O were responsible for the enhanced purity of the SPS products. Particle size was also a factor of influence with the most favourable results for density and minimised O/H concentrations achieved with particles §180 mm in diameter.

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The objective of this research was to assess the effects of compaction method (uni-axial die compaction and cold isostatic pressing) on two aluminium powder metallurgy alloys. Both systems were mixtures of elemental and master alloy powders. Mechanical and physical properties from samples prepared using both methods were compared. Analyses included the measurement of green and sintered densities, tensile properties and microstructural analyses. Results indicated that sintered products of a largely comparable quality could be realised for both alloys regardless of the compaction approach employed. PM2324 displayed sensitivity to compaction pressure such that low values were preferred for cold isostatic pressing (CIP) whereas higher values yielded superior sintered products when die compaction was implemented. Conversely, compaction pressure had no meaningful impact on the sintering behaviour of PM7075 for CIP or die pressed samples.Le but de cette recherche consistait à é valuer les effets de la mé thode de compaction (compaction uniaxe en moule et compression isostatique à froid) sur deux alliages d'aluminium de la mé tallurgie des poudres. Les deux systè mes consistaient en mé langes de poudres é lé mentaires et de poudres d'alliage mè re. On a comparé les proprié té s mé caniques et physiques des é chantillons pré paré s en utilisant les deux mé thodes. Les analyses incluaient la mesure de la densité à cru et fritté e, les proprié té s de traction et les analyses de la microstructure. Les ré sultats indiquaient que l'on pouvait ré aliser des produits fritté s d'une qualité trè s comparable pour les deux alliages, peu importe l'approche de compaction utilisé e. PM2324 dé montrait une sensitivité à la pression de compaction de telle sorte que des valeurs faibles é taient pré fé ré es pour le CIP alors que des valeurs plus é levé es produisaient des produits fritté s supé rieurs avec la compaction en moule. Inversement, la pression de compaction n'avait pas d'impact significatif sur le comportement de frittage de PM7075 pour les é chantillons pressé s par CIP ou en moule.

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