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Microstructures and deformation mechanisms of a G4 TiAl alloy produced by spark plasma sintering / H. Jabbar in Acta materialia, Vol. 59 N° 20 (Décembre 2011) 

Public ISBD [article]  in Acta materialia > Vol. 59 N° 20 (Décembre 2011) . - pp. 7574–7585 Titre : Microstructures and deformation mechanisms of a G4 TiAl alloy produced by spark plasma sintering Type de document : texte imprimé Auteurs : H. Jabbar, Auteur ; J.-P. Monchoux, Auteur ; M. Thomas, Auteur Année de publication : 2012 Article en page(s) : pp. 7574–7585 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Powder  consolidation  Scanning  and  transmission  electron  microscopy  Titanium  aluminides  Plastic  deformation Résumé : TiAl alloys are prepared by spark plasma sintering (SPS) using a pre-alloyed powder with the so-called G4 composition (Ti51Al47Re1W1Si0.2). SPS densifications are conducted using short and classical cycles, with various dwell temperatures. The microstructure of the products is studied by scanning and transmission electron microscopy. In particular, constituent phases, grain size, precipitates and local chemical composition are determined. A double phase γ + α2 microstructure containing B2 precipitates is found in a large range of sintering temperatures. Mechanical properties at RT and creep strength at 700 °C/300 MPa are measured. No significant improvement of the mechanical properties is obtained with respect to those of SPS-TiAl alloys previously sintered. A study of the deformation mechanisms and the effect of the microstructure on these mechanisms is performed. Hence, the strong effect of microstructural heterogeneities from the initial powder is demonstrated. ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645411006288 [article] Microstructures and deformation mechanisms of a G4 TiAl alloy produced by spark plasma sintering [texte imprimé] / H. Jabbar, Auteur ; J.-P. Monchoux, Auteur ; M. Thomas, Auteur . - 2012 . - pp. 7574–7585. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 59 N° 20 (Décembre 2011) . - pp. 7574–7585 Mots-clés : Powder  consolidation  Scanning  and  transmission  electron  microscopy  Titanium  aluminides  Plastic  deformation Résumé : TiAl alloys are prepared by spark plasma sintering (SPS) using a pre-alloyed powder with the so-called G4 composition (Ti51Al47Re1W1Si0.2). SPS densifications are conducted using short and classical cycles, with various dwell temperatures. The microstructure of the products is studied by scanning and transmission electron microscopy. In particular, constituent phases, grain size, precipitates and local chemical composition are determined. A double phase γ + α2 microstructure containing B2 precipitates is found in a large range of sintering temperatures. Mechanical properties at RT and creep strength at 700 °C/300 MPa are measured. No significant improvement of the mechanical properties is obtained with respect to those of SPS-TiAl alloys previously sintered. A study of the deformation mechanisms and the effect of the microstructure on these mechanisms is performed. Hence, the strong effect of microstructural heterogeneities from the initial powder is demonstrated. ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645411006288