Quantification of the chemical reactivity of molten nitrate salts with heat treatable aluminum alloys

Autor: J.-P. Harvey, Shanti Singh, Kentaro Oishi, Barbara Acheson, Richard Turcotte, Daniel Pilon, Jonathan Lavoie, Bernard Grange
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Materials & Design, Vol 198, Iss , Pp 109293- (2021)
Druh dokumentu: article
ISSN: 0264-1275
DOI: 10.1016/j.matdes.2020.109293
Popis: This work explores the conditions for safe heat treatment of aluminum alloys containing lithium and magnesium in molten sodium nitrate (NaNO3) bath furnaces, and conditions where industrial accidents may occur. Using calorimetry coupled to classical thermodynamics, the strength of classical thermodynamics when analyzing thermal curves was demonstrated through a series of small-scale thermal analyses of various aluminum alloys in contact with sodium nitrate. This system was selected to illustrate reactions that may lead to severe and violent heat effect phenomena. Using idealized binary alloys, severe oxidation of magnesium- and lithium-rich aluminum alloy samples were shown to occur near 500 °C, a temperature range dangerously close to the operating temperature of solution heat treatment furnaces in manufacturing processes of heat treatable aluminum alloy sheets used in the aerospace industry. Commercial aluminum alloys AW257, 2198, 2024, and 1050 were also assessed with the same tools. The temperature that needed to be reached for these commercial aluminum alloys to react with molten sodium nitrate was significantly higher than the normal operating temperature of a conventional solution heat treatment furnace.
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