Thesis (M.S.)--University of Wisconsin--Madison, 1959. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 25-26).

Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

An investigation of the properties of titanium-tin and titanium-tin-aluminium alloys, produced by powder metallurgy, has been carried out, using as the starting material titanium produced by the reduction of titanium tetrachloride with sodium. Specimens of unalloyed titanium with low porosities could be obtained after a single pressing and sintering operation and the mechanical properties of these specimens were comparable to those of arc-melted material. The addition of tin had a beneficial effect upon the compacting and sintering characteristics of the powder, as well as markedly affecting the mechanical properties. The preparation of titanium-tin-aluminium alloys was more difficult and, for satisfactory results, compacts had to be worked after sintering. By this means specimens with relatively low alloying additions could be prepared to give acceptable mechanical properties. When, however, the alloying contest exceeded a certain level, the compacts were exceptionally brittle. This is believed to be due to inherent brittleness associated with the composition and not to be due to the method of preparation. It is concluded that sodium-reduced titanium is a suitable starting material for the satisfactory fabrication of certain titanium alloys by powder metallurgy and that the use of these methods offers certain advantages over production by arc-melting. Further incidental investigations, during the progress of the work, were carried out into the wetting of titanium by molten tin, the structure of titanium after cooling at different rates and the constitution of certain titanium-tin-aluminium alloys.

The thesis presents some aspects of the physical metallurgy of uranium which are relevant to its use as a reactor fuel. Creep and swelling of the fuel may he influenced by the presence of impurity phases. In PART I, techniques have therefore been developed to identify inclusions by 1) metallographic examination of uranium to which the elements normally present as impurities, have been intentionally added, 2) metallographic classification of inclusions in cast uranium, 3) extraction of inclusions followed by examination of the residues. Inclusions have been classified into seven main types and their occurrence, form and chemical nature have been summarised together with their etching and optical characteristics. PART II describes the structural effects due to dilute additions of aluminium, iron, chromium, niobium, titanium, vanadium and zirconium. Emphasis is placed on their grain refining capacity during heat treatment because of the need to eliminate surface wrinkling of a fuel during irradiation. The differing degrees of beta-stabilisation obtained by the use of some of these elements may influence the extent of grain refinement. Data are presented on the uranium-rich ends of the uranium-aluminium and uranium-iron constitutional diagrams. PART III is an investigation into the creep properties of uranium and uranium alloys after various heat treatments using a sagging bar technique. PART IV examines the preferred orientation induced in uranium and uranium alloys by rolling and extrusion. A geiger counter technique is used to give a quantitative assessment. The various textures are all of a single or multiple (hke) types. Preferred orientation is undesirable in a reactor fuel because of irradiation growth, but it has been shown that beta heat treatment can substantially remove the texture.

The beginnings of metallurgy in Eurasia are contentious. The first cast copper objects in this region emerged c. 7000 years ago, and their production has been tentatively linked to centres in the Near East. This assumption, however, was not substantiated by the copper smelting evidence in those centres. The recent discovery of the world’s earliest copper smelting in Belovode, a Vinča culture site in eastern Serbia, dated at c. 5000 BC has changed our understanding on when and where metallurgy possibly first occurred. By extending the known record of copper smelting for more than half a millennium, and occurring at the location remote from the Near East, this evidence challenged the traditional model of a single origin of metallurgy and revived the possibility of multiple, independent inventions. However, the origins of metallurgy have usually been studied in isolation and detached from their technological, social and environmental context, and there has been little research specifically addressing how and why metallurgy evolved. This thesis explores the invention, innovation and cultural transmission of early metal technology within five Vinča culture settlements in the Balkans, using assemblages of high archaeometallurgical resolution. To these, copper mineral use in three Early Neolithic sites was included to explore metallurgy-related practices preceding the earliest record of smelting in the Vinča culture. Microstructural, chemical and provenance analyses of slags, copper minerals, malachite beads and metal artefacts reveal the technology of making and working, and potential sources of mineral exploitation. The interdisciplinary approach demonstrates the presence of an established metallurgical technology within the Vinča culture, which expanded across the 5th millennium BC Balkans, while provenance analysis indicates multiple sourcing for various local copper minerals. The interpretation of metallurgical data contributes significantly to understanding the origins of metallurgy in this part of Eurasia and strengthens the idea of multiple inventions.

No description available.

The Anglo Research Nickel (ArNi) process is a novel extractive metallurgical process that arose out of the need to develop a processing route for the recovery of nickel from lateritic ore deposits that is both economical and environmentally acceptable.

To produce crack free powder compacts with desirable mechanical properties and uniform densities, a predictive finite element simulation of the powder metallurgy process is necessary (compaction and sintering). The finite element method, through the use of appropriate constitutive material models captures the microstructure-property history after compaction and sintering. A FC-0205 cylinder and FC-0208 automotive main bearing cap were compacted to investigate the microstructure changes at different locations within the parts. Measurements of the pore volume fraction, pore size, pore nearest neighbor, pore aspect ratio, and grain size were performed after compaction for the cylinder after compaction and after compaction and sintering for the MBC. An image analysis methodology was created to measure density in the main bearing cap, and to validate future model results. A comparison between the image analysis and the Archimedes immersion methods demonstrated the reliability of the methods.

<p>The inclusions are harmful to the steel cleanliness; process parameters such as stirring and steel and slag oxidation must be controlled to obtain a final number of inclusions in the steel whose size is smaller than the critical size for each steel product.</p> <p>A simple mathematical model was developed to analyze the impact of bubbling, slag and initial oxidation level on inclusion distribution control (quantity and size of them) during the process in a Ladle Metallurgy Furnace (LMF).</p> <p>The initial inclusion size distribution is calculated and adjusted with the samples analyzed by SEM-EDAX, this initial distribution decreases by removal mechanisms such as bubbling and slag and they can increases by reoxidation.</p> <p>The model allows predicting the inclusion removal by bubbling mechanism as a function of gas flow rate and inclusion size and it proves which a softer stirring is better for removal inclusion than stronger one. An interesting point analyzed is the effect of stirring level on small and large inclusions.</p> <p>According to the inclusion number removal by slag, it is possible to appreciate like larger inclusions are removed easier than smaller ones. This mechanism is the most important to remove inclusions calculated by this model.</p> / Master of Science (MSc)