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

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [119]-133).

Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2006. / Gokhale, Arun, Committee Chair ; Gall, Ken, Committee Member ; Thadhani, Naresh, Committee Member.

Thesis (Ph. D.)--Ohio State University, 2006. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2007 Feb 28

Thesis (Ph. D.)--Ohio State University, 2005. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2006 Nov 30

No description available.

published_or_final_version / abstract / Mechanical Engineering / Doctoral / Doctor of Philosophy

m alloys used in automotive, aerospace and military applications. Superplasticity requires fine grains with high-angle boundaries and resistance to failure by cavitation. OIM permits grain-specific orientation determination and quantitative assessment of the grain-to-grain disorientation distribution as well as grain size measurement in materials. The current work offers significant new insights into the development and response of superplastic microstructures; in particular, OIM data may be employed to delineate the transition from slip to grain boundary sliding in superplastic 5083 materials. / US Navy (USN) author

A research dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering, 2016 / The Fe-Al alloys have been viewed as attractive for applications in the energy sector, for example boilers and pipes in power plants. As such, improvement of the properties of an Fe-40 at.% Al alloy were attempted by adding small amounts of precious metal to the alloy. An Fe-40 at.% Al alloy produced by melting and casting in a button arc furnace, showed very large grains in the microstructure and had a hardness of ~400HV. Precious metals (Ag, Ru, Pt, Pd) were added in amounts of either 0.2 at.% or 0.5 at.%. Additions of Ag and Ru were found to decrease the hardness, but the addition of Pt and Pd did not affect the hardness significantly. Oxidation testing of the alloys showed that they were very resistant to oxidation, although there was some small internal oxides in the sample containing Pt. Corrosion testing of the samples showed that the precious metals helped to greatly decrease the corrosion rate of the FeAl alloy in H2SO4. The mechanical alloying and sintering parameters were first optimised using the plain FeAl alloy and the sintered plain FeAl had significantly smaller grains than the as-cast material under all conditions, and that the hardness had increased as a result. The mechanical alloying also produced a carbide phase in the material that was not able to be removed. After mechanical alloying and sintering of the precious metal containing alloys, the microstructure had been refined slightly more than plain FeAl in all the alloys, except that containing Ru, which was the same as the plain alloy. The presence of Pt and Pd increased the hardness of the alloy slightly, while Ru and Ag produced no change. Oxidation testing showed that the sintered compacts had significantly less grain growth than the as-cast samples, and that generally the oxidation resistance was good. The exception to this was the sample containing Pd, which showed sub-surface oxidation. Corrosion testing of the sintered compacts showed that the Ru and Pt containing alloys performed better than the as-cast alloys. Both the Pd and Ag containing samples suffered from pitting, and the Pd sample was corroded away completely during the test in 3.8M H2SO4 solution. It was concluded that there was a significant effect on the microstructure of the FeAl alloy due to the processing route used, and that this also produced a significant effect on the hardness and corrosion resistance, with both improving when non-equilibrium processing was used. The presence of precious metals in small amounts increased the corrosion resistance of the alloy, and overall, only produced small changes in the hardness, and oxidation properties of the alloy. / GR2016

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg 1988 / Fatigue crack closure characteristics were studied in a 70i7 aluminium alloy in the as received (AR) and heat treated (HT) conditions with the view of establishing the general closure trends and how well the modified closure parameter AKeff (- K^ax ' K0_) was capable of characterising fatigue crack growth. The results of this work indicated that a significant amount of strain intensification occurred below K0p which implied that AKe££ generally underestimated the stress intensity range experienced at the crack tip during cyclic loading. The major objective of this dissertation was to determin' whether a relationship exists between the distance over which closure develops from zero to a steady state jlcsure value, and the distance over which short crack growth behaviour occurs. Two techniques were used to eliminate closure for a fatigue crack in a compact temion specimen. Closure development was then measured as a function crack length and a steady state closure value was approached tier about 0.19 mm in the AR material and 0.?8 mm in the HT material irrespective of AK. This distance compared well with that distance over which short cracks exhibited "anomalous" behaviour. This implies that anomalous short ctack behaviour is dependent on the distance over which closure develops in this alloy, although microstructural influences may play a rola.