Documents disponibles écrits par cet auteur

Effect of exposure in steam or argon on the creep properties of Ni-based alloys / S. Dryepondt in Materials and corrosion, Vol. 63 N° 10 (Octobre 2012) 

Public ISBD [article]  in Materials and corrosion > Vol. 63 N° 10 (Octobre 2012) . - pp. 889–895 Titre : Effect of exposure in steam or argon on the creep properties of Ni-based alloys Type de document : texte imprimé Auteurs : S. Dryepondt, Auteur ; K. A. Unocic, Auteur ; B. A. Pint, Auteur Année de publication : 2013 Article en page(s) : pp. 889–895 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Creep;  gamma  prime  precipitates;  Ni  based  superalloys;  oxidation;  steam Résumé : Although expensive, Ni-based superalloys are of interest for the ultrasupercritical steam program because of their good creep and oxidation resistance at temperatures above 700 °C. As the effect of steam oxidation on the alloy mechanical properties is unknown, creep specimens of alloy CCA617, 740, and 230 were pre-oxidized for 2000 and 4000 h in steam at 800 °C before testing in air at the same temperature. Compared with as fabricated material, exposure in steam decreased the creep properties of alloy CCA617, had less of an effect on alloy 740, and did not affect alloy 230. Testing of a specimen repolished after steam exposure as well as microstructural observations indicate that the oxidation affected zone at the specimen surface is not responsible for the properties degradation. Surprisingly, a similar time anneal in an inert environment resulted in a drastic decrease of creep rupture life and an increase in the creep rate and elongation at rupture. Transmission electron microscopy analysis revealed that the mechanical properties decrease for alloy CCA617 is related to the absence of γ′ precipitates within the grains. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201206694/abstract [article] Effect of exposure in steam or argon on the creep properties of Ni-based alloys [texte imprimé] / S. Dryepondt, Auteur ; K. A. Unocic, Auteur ; B. A. Pint, Auteur . - 2013 . - pp. 889–895. Génie mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 63 N° 10 (Octobre 2012) . - pp. 889–895 Mots-clés : Creep;  gamma  prime  precipitates;  Ni  based  superalloys;  oxidation;  steam Résumé : Although expensive, Ni-based superalloys are of interest for the ultrasupercritical steam program because of their good creep and oxidation resistance at temperatures above 700 °C. As the effect of steam oxidation on the alloy mechanical properties is unknown, creep specimens of alloy CCA617, 740, and 230 were pre-oxidized for 2000 and 4000 h in steam at 800 °C before testing in air at the same temperature. Compared with as fabricated material, exposure in steam decreased the creep properties of alloy CCA617, had less of an effect on alloy 740, and did not affect alloy 230. Testing of a specimen repolished after steam exposure as well as microstructural observations indicate that the oxidation affected zone at the specimen surface is not responsible for the properties degradation. Surprisingly, a similar time anneal in an inert environment resulted in a drastic decrease of creep rupture life and an increase in the creep rate and elongation at rupture. Transmission electron microscopy analysis revealed that the mechanical properties decrease for alloy CCA617 is related to the absence of γ′ precipitates within the grains. En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201206694/abstract

Performance of Al-rich oxidation resistant coatings for Fe-base alloys / B. A. Pint in Materials and corrosion, Vol. 62 N° 6 (Juin 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 6 (Juin 2011) . - pp. 549–560 Titre : Performance of Al-rich oxidation resistant coatings for Fe-base alloys Type de document : texte imprimé Auteurs : B. A. Pint, Auteur ; Y. Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 549–560 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Coating  Ferritic  alloys  Austenitic  alloys  H2O  effect  Interdiffusion  Lifetime  model Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The oxidation resistance of Al-rich coatings made by chemical vapor deposition and pack cementation was examined on representative ferritic-martensitic (FM, e.g. Grade 91, Fe-9Cr-1Mo) and austenitic steel substrates at 650°-800 °C. To evaluate the potential benefits and problems with these alumina-forming coatings, oxidation exposures were conducted in a humid air environment where the uncoated substrates experience rapid oxidation, similar to steam. Exposure temperatures were increased to accelerate failure by oxidation and interdiffusion of Al into the substrate. The difference in the coefficient of thermal expansion (CTE) between coating and substrate was found to cause cracking and coating failure during rapid thermal cycling on thicker coatings with Fe-Al intermetallic phases. Therefore, thinner coatings with less Al and a ferritic Fe(Al) structure were evaluated more extensively and tested to failure at 700° and 800 °C on FM steels. The remaining Al content at failure was measured and used to improve a previously developed coating lifetime model. At 700° and 800 °C, thin coated austenitic specimens continue to exhibit protective behavior at more than double the lifetime of a similar coating on FM steel. The longer lifetime was attributed to the ferritic coating-austenitic substrate phase boundary inhibiting Al interdiffusion. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005884/abstract [article] Performance of Al-rich oxidation resistant coatings for Fe-base alloys [texte imprimé] / B. A. Pint, Auteur ; Y. Zhang, Auteur . - 2011 . - pp. 549–560. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 6 (Juin 2011) . - pp. 549–560 Mots-clés : Coating  Ferritic  alloys  Austenitic  alloys  H2O  effect  Interdiffusion  Lifetime  model Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The oxidation resistance of Al-rich coatings made by chemical vapor deposition and pack cementation was examined on representative ferritic-martensitic (FM, e.g. Grade 91, Fe-9Cr-1Mo) and austenitic steel substrates at 650°-800 °C. To evaluate the potential benefits and problems with these alumina-forming coatings, oxidation exposures were conducted in a humid air environment where the uncoated substrates experience rapid oxidation, similar to steam. Exposure temperatures were increased to accelerate failure by oxidation and interdiffusion of Al into the substrate. The difference in the coefficient of thermal expansion (CTE) between coating and substrate was found to cause cracking and coating failure during rapid thermal cycling on thicker coatings with Fe-Al intermetallic phases. Therefore, thinner coatings with less Al and a ferritic Fe(Al) structure were evaluated more extensively and tested to failure at 700° and 800 °C on FM steels. The remaining Al content at failure was measured and used to improve a previously developed coating lifetime model. At 700° and 800 °C, thin coated austenitic specimens continue to exhibit protective behavior at more than double the lifetime of a similar coating on FM steel. The longer lifetime was attributed to the ferritic coating-austenitic substrate phase boundary inhibiting Al interdiffusion. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.201005884/abstract