Novelis Global Technology Centre (NGTC) in Kingston, Ontario have been developing a relatively new technology known as Novelis Fusion™ Technology, which is a new variant of the traditional direct chill (DC) casting process that allows co-casting of multi-layered composite aluminum alloy ingots. One of the first steps in this development program is to create a mathematical model of conventional DC casting and validate it through experimentation before proceeding to the next step of modeling, designing, testing, and experimenting with the co casting process. The focus of this document is on the design of the experiments, measurement technique, and analysis of the experimental results to be used to validate the models for conventional DC casting. A series of experiments was conducted using a lab scale caster using a 95 mm × 227 mm rectangular mould available at the Novelis Global Technology Centre in Kingston, Ontario. AA3003, AA6111, and AA4045 aluminum alloys were chosen for this study since these aluminum alloys are commonly used in clad products. Two series of experiments were performed to investigate the effect of casting parameters on the solidification and cooling of the ingots such as casting speed, water flow rate, and the superheat of the molten aluminum. A set of seven thermocouples were embedded in the ingot during the cast to capture the thermal history of the ingot. Melt poisoning with a zinc rich alloy was also performed as an independent method of determining the sump depth and shape. Experienced gained from the first series of experiments allowed improvements to be made to the experiment design for the second series of experiments. Thermocouples must be supported so they are not pushed out of position by the jet of molten aluminum entering the mould. Grounded thermocouples of at least 1.5 mm in diameter were recommended to survive the high temperatures of the molten aluminum. Knowledge gained from the experiments of the conventional DC caster allowed design and development of an experimental co-caster mould that will be useful for future research at NGTC. Melt poisoning and thermocouples were complementary measurement methods that should be used together. In all three alloys, the liquidus sump profile generated by the thermocouple implants correlated well with the etched sumps of the melt poisoned ingots. Primary and secondary water flow rates beyond 1.79 L/s and increasing the superheat by 30°C did not have significant effect of the cooling rate with solidified ingots, but all casting experiments showed that the thermal histories and sump profiles were very sensitive to the casting speed. The sump depth increased with increasing casting speed in all casting experiments. The sump depth increased directly proportionally to the Péclet number and the sump depth could be predicted using a linear regression model by calculating the Péclet number. The formation of remelting bands were seen in the surface of the AA3003 and AA4045 ingots, but were not apparent in the AA6111 ingots. A fast Fourier transform performed on the data obtained from the thermocouples that were inserted in the mould wall showed that remelting occurred at regular intervals and that the frequency increased with casting speed. The thermocouples in the mould also indicated that AA6111 had a higher rate of heat transfer than AA3003 or AA4045. The AA6111 ingots had a higher rate of heat transfer in the mould than for the other alloys. This was evidence that there was a smaller air gap formation between the ingot and the mould in AA6111. This research on the effects of casting parameters on DC cast ingots made using the three alloys, AA3003, AA6111, and AA4045, is beneficial in the development of a design of an experimental lab-scale co-caster for validation of a computational fluid dynamics (CFD) model of the Fusion™ Technology process.

The influence of manganese (Mn) addition on the tensile properties of recovery-annealed aluminum alloy sheet was studied. After 200 ~ 220¢X C annealing, these alloys exhibit hardening as compared to the as-rolled state. Besides the amount of Mn in solution, the presence of Fe and Si in these alloys was also a vital factor responsible for the hardening. These recovery annealed aluminum alloy sheets show increased tensile elongation with increasing annealing temperature, which is mainly due to the contribution of post-uniform elongation (PUE). The plastic deformation during PUE is associated with development of fine slip bands distributed in the gauge length of the specimen. It was noted that after recovery anneal, the alloy with 0.74 wt% Mn exhibit better combination of strength and ductility as compared to alloys with lower Mn content. In general, these alloys in partially annealed condition show poor tensile ductility at RT, which is mainly attributed to the low work hardening rate associated with the UFG structure. These partially annealed aluminum alloys exhibit highly anisotropic tensile properties, specially a rather poor ductility along the direction of 45o or 90o from the rolling direction at RT. The poor ductility in 45o or 90o direction could be related to flow localization associated with intense shear banding. Discontinuous yielding plays a pivotal role to trigger the flow localization which is affected by the strain path change. However, for alloys tested at 77 K in 45¢X or 90¢X direction, the deformation proceeds by the propagation of Lüders band initially and followed by strain hardening. In general, the tensile elongation can be enhanced greatly irrespective of the stress direction, because a higher work hardening rate can be maintained due to reduced dynamic recovery rate. The yield stress is orientation dependent, which is in the order of 90¢X > 0¢X > 45¢X. The anisotropic tensile behavior has its origin in the rolling texture. The Schmid factor analysis indicates that specimens tested in 45o direction would have lower yield strength as compared to those tested in 0o or 90o direction. Both experimental measurements and simulation indicate that after 30% tensile straining, the copper texture in the partially annealed aluminum alloy is enhanced 0¢X test, and the brass texture is enhanced in 90¢X test, while the texture distribution does not change significantly in 45¢X test. It is suggested that the texture evolution during tensile straining has significant effect on the anisotropy of work hardening rate.

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 228-234).

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains vii, 93 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 71-75).

Thesis (Ph. D.)--University of Queensland, 2001. / Includes bibliographical references.

Thesis (Ph. D.)--University of Michigan, 1946. / Reproduced from type-written copy. Bibliography: leaves 43-44.

Thesis (Ph. D.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xix, 233 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 223-233).

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: hydrogen removal; metal cleaning; particle removal. Includes bibliographical references (p. 42-43).

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