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This work demonstrates that bulk ultrafine-grained zirconium can be fabricated by accumulative roll bonding. Grain refinement takes place by geometrical thinning and grain subdivision through the formation of geometrically necessary boundaries. This is consistent with the stabilization of a typical rolling texture during processing and with the absence of any recrystallization texture components....
In principle, hydrogen can be applied as a reducing agent for the production of many metals. It has found commercial application for the synthesis of platinum group metals, some rare metals such as germanium and rhenium, and for the production of special grades of metals (e.g., fine nickel and cobalt powders) However, hydrogen is primarily applied for the synthesis of tungsten and molybdenum, with...
Ultra-high-purity niobium sheet is used to fabricate radio frequency cavities for use in future linear accelerators. The complexity of the shapes requires the electron-beam welding of deep-drawn components, but difficulties with inconsistent formability, springback, and surface roughness have been traced to non-uniform microstructures and texture gradients that are common in commercial niobium sheet...
In this article, experimental studies for the nitriding of four titanium alloys at different temperatures and for different periods of time are summarized. The studies focused on microstructural changes in relation to the alloy composition and processing parameters; microindentation hardness testing on the nitrided titanium alloys to analyze their hardness evolution; and the corrosion behavior of...
The formation of TiCxNy coatings on titanium alloys through thermochemical treatment of graphite in nitrogen was investigated in this study. The presence of oxygen in saturating media was found to lower the nitrocarburizing temperature from 1,100°C to 850°C. Two methods to accumulate oxygen in a saturating medium have been proposed: using oxygen-containing nitrogen or oxygensaturated graphite. The...
Alloys from the Nb-W-Cr system have been investigated for possible application at temperatures above 1,000°C. In this study, Nb-20W-5Cr (compositions are in weight percent) and Nb-20W-10Cr alloys were exposed to air for both 24 hours and 168 hours in a temperature range of 700°C to 1,400°C in order to determine the oxidation resistance. Although extensive powder formation at temperatures below 1,000°C...
Titanium is the material of choice for a wide variety of applications. However, because of its relatively high price—a result of extraction and processing costs—it is used only when it is the only choice. This paper will overview the potential areas that are amenable to cost reduction for titanium products, emphasizing all steps in component fabrication from extraction and processing to the fabrication...
When it was discovered in 1669, phosphorus became a wonder of the European courts and fairs, with the chemiluminescent combination of phosphorus and atmospheric oxygen producing a light show no one had ever seen before or even thought possible. Within ten years of its discovery, a new curiosity emerged when Robert Boyle improved the production method by adding SiO2 to the mix, then coating paper with...
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