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Wetting phenomena of Al–Cu alloys on sapphire below 800 °C / Andreas J. Klinter in Acta materialia, Vol. 58 N° 4 (Fevrier 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 4 (Fevrier 2010) . - pp. 1350–1360 Titre : Wetting phenomena of Al–Cu alloys on sapphire below 800 °C Type de document : texte imprimé Auteurs : Andreas J. Klinter, Auteur ; Carlos A. Leon-Patiño, Auteur ; Robin A.L. Drew, Auteur Année de publication : 2011 Article en page(s) : pp. 1350–1360 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Wetting  Al–Cu  alloys  Sapphire  Thermodynamic  modeling  Interfaces Résumé : Using a modified dispensed drop method, a decrease in contact angle on sapphire from pure aluminum to low-copper-containing Al alloys (7–12 wt.%) was found; with higher copper additions θ transitions to the non-wetting regime. Atomic force microscopy on long-term samples showed a significantly increased surface roughness beneath the drop. Using high-resolution transmission electron microscopy, the reaction product at the interface was identified as CuAl2O4 for Al–7Cu and Al2O3 for an Al–99.99 drop. X-ray photoelectron spectroscopy further confirmed the formation of CuAl2O4 under CuAl2 drops. Spinel formation is caused by reaction of the alloy with residual oxygen in the furnace that is transported along the interface as modeled by thermodynamic simulations. The formation of CuAl2O4 causes the reduced σsl and hence the improved wettability of sapphire by low-copper-containing alloys compared to pure aluminum. The main reason for the increase in θ with higher copper contents is the increasing σlv of the alloy. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409007435 [article] Wetting phenomena of Al–Cu alloys on sapphire below 800 °C [texte imprimé] / Andreas J. Klinter, Auteur ; Carlos A. Leon-Patiño, Auteur ; Robin A.L. Drew, Auteur . - 2011 . - pp. 1350–1360. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 4 (Fevrier 2010) . - pp. 1350–1360 Mots-clés : Wetting  Al–Cu  alloys  Sapphire  Thermodynamic  modeling  Interfaces Résumé : Using a modified dispensed drop method, a decrease in contact angle on sapphire from pure aluminum to low-copper-containing Al alloys (7–12 wt.%) was found; with higher copper additions θ transitions to the non-wetting regime. Atomic force microscopy on long-term samples showed a significantly increased surface roughness beneath the drop. Using high-resolution transmission electron microscopy, the reaction product at the interface was identified as CuAl2O4 for Al–7Cu and Al2O3 for an Al–99.99 drop. X-ray photoelectron spectroscopy further confirmed the formation of CuAl2O4 under CuAl2 drops. Spinel formation is caused by reaction of the alloy with residual oxygen in the furnace that is transported along the interface as modeled by thermodynamic simulations. The formation of CuAl2O4 causes the reduced σsl and hence the improved wettability of sapphire by low-copper-containing alloys compared to pure aluminum. The main reason for the increase in θ with higher copper contents is the increasing σlv of the alloy. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409007435