In metallurgy, alpha case is the oxygen-enriched surface phase that occurs when titanium and its alloys are exposed to heated air or oxygen. Alpha case is hard and brittle, and tends to create a series of microcracks that will reduce the metal's performance and its fatigue properties. Alpha case can be minimized or avoided by processing titanium at very deep vacuum levels. However once present on the surface, the currently applied method to remove the alpha case is by the subtractive methods of machining and/or chemical milling. An emerging technique is to subject the metal to an electrochemical treatment in molten salts, such as calcium chloride or lithium chloride at elevated temperatures. This method removes the dissolved oxygen from the alpha case, hence restoring the oxygen-free metal. However, an unwanted consequence of the high temperature treatment is the growth of the grains in the metal. Grain growth may be limited by lowering the molten salt temperature. Alternatively, the metal may be rolling-pressed again to break the large grains into smaller ones.[1]
Referencesedit
^George, Zheng Chen; Derek J. Fray; Tom W. Farthing (17 April 2007). "Cathodic deoxygenation of the alpha case on titanium and alloys in molten calcium chloride". Metallurgical and Materials Transactions B. 32 (6). Springer Boston: 1041–1052. doi:10.1007/s11663-001-0093-8. S2CID 95616531.
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alpha, case, metallurgy, alpha, case, oxygen, enriched, surface, phase, that, occurs, when, titanium, alloys, exposed, heated, oxygen, hard, brittle, tends, create, series, microcracks, that, will, reduce, metal, performance, fatigue, properties, minimized, av. In metallurgy alpha case is the oxygen enriched surface phase that occurs when titanium and its alloys are exposed to heated air or oxygen Alpha case is hard and brittle and tends to create a series of microcracks that will reduce the metal s performance and its fatigue properties Alpha case can be minimized or avoided by processing titanium at very deep vacuum levels However once present on the surface the currently applied method to remove the alpha case is by the subtractive methods of machining and or chemical milling An emerging technique is to subject the metal to an electrochemical treatment in molten salts such as calcium chloride or lithium chloride at elevated temperatures This method removes the dissolved oxygen from the alpha case hence restoring the oxygen free metal However an unwanted consequence of the high temperature treatment is the growth of the grains in the metal Grain growth may be limited by lowering the molten salt temperature Alternatively the metal may be rolling pressed again to break the large grains into smaller ones 1 References edit George Zheng Chen Derek J Fray Tom W Farthing 17 April 2007 Cathodic deoxygenation of the alpha case on titanium and alloys in molten calcium chloride Metallurgical and Materials Transactions B 32 6 Springer Boston 1041 1052 doi 10 1007 s11663 001 0093 8 S2CID 95616531 nbsp This industry related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Alpha case amp oldid 1119037475, wikipedia, wiki, book, books, library,
