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Production of nanocrystalline aluminium alloy powders through cryogenic milling and consolidation by dynamic magnetic compactionSeminari, Umugaba. January 2007 (has links)
Nanopowders and bulk nanostructred materials have gained large interest in recent years. Bulk nanostructured materials exhibit properties that are far superior in comparison to conventional micron grained alloys. The fabrication of large scale nano-grained materials has been achieved in a two step process: (1) the production of nanostructured aluminium alloy powders and (2) the consolidation of the powder using a electromagnetic shockwave process. / The first part consists of cryo-milling; the milling of powder in an attritor filled with liquid nitrogen. This causes successive welding and fracturing events as the powder is milled, thereby creating the nano-structure. The low temperature prevents the possibility of recrystallization and grain growth. The alloy used for this work was Al 5356 (Al-5%Mg). Two different types of raw source materials were investigated: pre-alloyed powders and a mixture of aluminum with pure magnesium or an Al12Mg17 intermetallic. Experiments have been conducted in order to determine the optimum milling parameters that will simultaneously give a grain size smaller than 100 nm; equiaxed milled particles and mechanically alloyed powder (in the case of the mixture). The optimum milling parameters were established at 15 hours of milling time with a rotational speed of 300 RPM and ball to powder weight ratio of 24:1 in the case of the pre-alloyed powders. For the mixture of pure aluminum with pure magnesium the parameters were 15 hours, 300RPM and 32:1. The parameters for the mixture with the intermetallic were 18 hours, 300RPM and 32:1. / The dynamic magnetic compaction technique was done with a peak pressure of 1.1 GPa. This ultra-high strain rate process minimizes the exposure of the powders to high temperature and therefore reduces the possibility of recrystallization and grain growth. Relative densities of compacted pieces obtained ranged from 86.39% to 97.97%. However consolidation characterized by particle to particle bonding with a melted layer was not accomplished.
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The mechanism of aluminosilicate formation in alumina refining /Zheng, Kali. Unknown Date (has links)
Thesis (PhD)--University of South Australia, 1997
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The influence of molten metal surface properties on the formation of surface defects on vertical direct chill cast aluminium alloy productsBainbridge, Ian Frank. Unknown Date (has links)
No description available.
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Characterization and mechanical properties of nanoscale precipitates in modified Al-Si-Cu alloys using transmission electron microscopy and 3D atom probe tomographyHwang, Junyeon. Kaufman, M. J., January 2007 (has links)
Thesis (Ph. D.)--University of North Texas, May, 2007. / Title from title page display. Includes bibliographical references.
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Development of constitutive model for AL-2011 in mushy stateWang, Shun-sheng. January 1994 (has links)
Thesis (Ph. D.)--Ohio University, March, 1994. / Title from PDF t.p.
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On the compressive response of open-cell aluminum foamsJang, Wen-yea, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.
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Experimental and numberical study of elastic-plastic mixed-mode fracture /Zafari, Farzad. January 1997 (has links)
Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [227]-234).
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Prédiction de la rupture par fatigue dans les pièces automobiles en alliages aluminium /Saoudi, Abdelhamid, January 2008 (has links)
Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2008. / La p. de t. porte en outre: Doctorat en ingénierie, thèse pour l'obtention du titre de Philosophiae Doctor en ingénierie. CaQQUQ Comprend des réf. bibliogr. (f. 174-178). Publié aussi en version électronique. CaQQUQ
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Effet des additifs sur la microstructure et les propriétés mécaniques des alliages d'aluminium-silicium /Mohamed, Adel, January 2008 (has links)
Thèse (D.Eng..) -- Université du Québec à Chicoutimi, 2008. / La p. de t. porte en outre: Thèse présenté[e] à l'Université du Québec à Chicoutimi comme exigence partielle du doctorat en ingénierie. CaQQUQ Comprend des réf. bibliogr. (f. [292]-314). Publié aussi en version électronique. CaQQUQ
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Développement d'un système de contrôle de qualité pour les lopins d'aluminium semi-solide[s] obtenus avec le procédé SEED /Blanchette, Hugues, January 2006 (has links)
Thèse (M.Eng.) -- Université du Québec à Chicoutimi, 2006. / Bibliogr.: f. 127-129. Document électronique également accessible en format PDF. CaQCU
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