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Computational design of corrosion-resistant Fe–Cr–Ni–Al nanocoatings for power generation / K. S. Chan in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 5 (Mai 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 5 (Mai 2010) . - 09 p. Titre : Computational design of corrosion-resistant Fe–Cr–Ni–Al nanocoatings for power generation Type de document : texte imprimé Auteurs : K. S. Chan, Auteur ; W. Liang, Auteur ; N. S. Cheruvu, Auteur Année de publication : 2011 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Aluminium  compounds  Chromium  compounds  Corrosion  protective  coatings  Corrosion  resistance  Gas  turbines  Iron  compounds  Mechanical  engineering  computing  Nanostructured  materials  Nickel  compounds  Phase  diagrams  Steam  turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A computational approach has been undertaken to design and assess potential Fe–Cr–Ni–Al systems to produce stable nanostructured corrosion-resistant coatings that form a protective, continuous scale of alumina or chromia at elevated temperatures. The phase diagram computation was modeled using the THERMO-CALC® software and database (Thermo-Calc® Software, 2007, THERMO-CALC for Windows Version 4, Thermo-Calc Software AB, Stockholm, Sweden; Thermo-Calc® Software, 2007, TCFE5, Version 5, Thermo-Calc Software AB, Stockholm, Sweden) to generate pseudoternary Fe–Cr–Ni–Al phase diagrams to help identify compositional ranges without the undesirable brittle phases. The computational modeling of the grain growth process, sintering of voids and interface toughness determination by indentation, assessed microstructural stability, and durability of the nanocoatings fabricated by a magnetron-sputtering process. Interdiffusion of Al, Cr, and Ni was performed using the DICTRA® diffusion code (Thermo-Calc Software®, DICTRA, Version 24, 2007, Version 25, 2008, Thermo-Calc Software AB, Stockholm, Sweden) to maximize the long-term stability of the nanocoatings. The computational results identified a new series of Fe–Cr–Ni–Al coatings that maintain long-term stability and a fine-grained microstructure at elevated temperatures. The formation of brittle sigma-phase in Fe–Cr–Ni–Al alloys is suppressed for Al contents in excess of 4 wt %. The grain growth modeling indicated that the columnar-grained structure with a high percentage of low-angle grain boundaries is resistant to grain growth. Sintering modeling indicated that the initial relative density of as-processed magnetron-sputtered coatings could achieve full density after a short thermal exposure or heat-treatment. The interface toughness computation indicated that the Fe–Cr–Ni–Al nanocoatings exhibit high interface toughness in the range of 52–366 J/m2. The interdiffusion modeling using the DICTRA software package indicated that inward diffusion could result in substantial to moderate Al and Cr losses from the nanocoating to the substrate during long-term thermal exposures. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000005 [...] [article] Computational design of corrosion-resistant Fe–Cr–Ni–Al nanocoatings for power generation [texte imprimé] / K. S. Chan, Auteur ; W. Liang, Auteur ; N. S. Cheruvu, Auteur . - 2011 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 5 (Mai 2010) . - 09 p. Mots-clés : Aluminium  compounds  Chromium  compounds  Corrosion  protective  coatings  Corrosion  resistance  Gas  turbines  Iron  compounds  Mechanical  engineering  computing  Nanostructured  materials  Nickel  compounds  Phase  diagrams  Steam  turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A computational approach has been undertaken to design and assess potential Fe–Cr–Ni–Al systems to produce stable nanostructured corrosion-resistant coatings that form a protective, continuous scale of alumina or chromia at elevated temperatures. The phase diagram computation was modeled using the THERMO-CALC® software and database (Thermo-Calc® Software, 2007, THERMO-CALC for Windows Version 4, Thermo-Calc Software AB, Stockholm, Sweden; Thermo-Calc® Software, 2007, TCFE5, Version 5, Thermo-Calc Software AB, Stockholm, Sweden) to generate pseudoternary Fe–Cr–Ni–Al phase diagrams to help identify compositional ranges without the undesirable brittle phases. The computational modeling of the grain growth process, sintering of voids and interface toughness determination by indentation, assessed microstructural stability, and durability of the nanocoatings fabricated by a magnetron-sputtering process. Interdiffusion of Al, Cr, and Ni was performed using the DICTRA® diffusion code (Thermo-Calc Software®, DICTRA, Version 24, 2007, Version 25, 2008, Thermo-Calc Software AB, Stockholm, Sweden) to maximize the long-term stability of the nanocoatings. The computational results identified a new series of Fe–Cr–Ni–Al coatings that maintain long-term stability and a fine-grained microstructure at elevated temperatures. The formation of brittle sigma-phase in Fe–Cr–Ni–Al alloys is suppressed for Al contents in excess of 4 wt %. The grain growth modeling indicated that the columnar-grained structure with a high percentage of low-angle grain boundaries is resistant to grain growth. Sintering modeling indicated that the initial relative density of as-processed magnetron-sputtered coatings could achieve full density after a short thermal exposure or heat-treatment. The interface toughness computation indicated that the Fe–Cr–Ni–Al nanocoatings exhibit high interface toughness in the range of 52–366 J/m2. The interdiffusion modeling using the DICTRA software package indicated that inward diffusion could result in substantial to moderate Al and Cr losses from the nanocoating to the substrate during long-term thermal exposures. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000005 [...]