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1363 |
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Wednesday, June 04, 2008, Auditorium 2 9:20 AM Cold Spraying 1 Everything around this young thermal spraying technique, possible applications and latest developments for equipment of high pressure and low pressure cold spraying, models and simulations for a deeper process knowledge |
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Cold spray produced bulk forms |
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Jegan Karthikeyan* / ASB Industries, USA Charles Kay / ASB Industries, USA |
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The footprint of a cold spray beam has narrow dimensions and a large particle density, which lead to fast growth of deposit on precise locations. Cold spray produces compressively stressed coatings which lead to well bonded ultrathick coatings over many substrates. Since cold spray produces dense coatings with wrought-like microstructure, it can be used to produce large bulk forms. Two different bulk forms were produced: (i) ultrathick coatings, strongly bonded to substrates and (ii) free standing structures (FSS). Both forms were post machined to obtain net-shape or near-net-shape articles. Bulk forms were produced with many powders including metals (aluminum, copper, titanium, tantalum), alloys (SS, Inconels, MCrAlY) and composites (Al-B4C and others). Coating thickness was varied in the range of 1.0 ? 60 mm. Well bonded ultrathick coatings were produced over many substrates including aluminum, copper, SS, etc. As expected, bond strength varied with coating and substrate materials, and decreased with coating thickness. FSS were produced by fabrication of a mandrel, spray coating bulk forms and removal of the mandrel. FSS including pipes (150 mm diameter x 12 mm wall thickness), plates (200x200x15 mm), etc were produced. Coatings in the as-sprayed condition were machined and fine features such as grooves incorporated to obtain net-shape articles. |