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Phase transformations in nickel sulphide / Oussama Yousfi in Acta materialia, Vol. 58 N° 9 (Mai 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 9 (Mai 2010) . - pp. 3367–3380 Titre : Phase transformations in nickel sulphide : Microstructures and mechanisms Type de document : texte imprimé Auteurs : Oussama Yousfi, Auteur ; Patricia Donnadieu, Auteur ; Bréchet, Yves, Auteur Année de publication : 2011 Article en page(s) : pp. 3367–3380 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Nickel  sulphides  Phase  transformation  Microstructure  Massive  transformation  Diffusive  transformation Résumé : Nickel sulphide inclusions are known to be responsible for delayed fracture in tempered glasses due to phase transformation within the inclusion. Microstructural identification of the phase transformation mechanisms in the Ni–S system close to the NiS composition were carried out on a series of partially transformed states. Observations allow to investigate the morphological evolution during transformation, the phase orientation relationships and the first stages of the transformation were investigated by optical microscopy, electron backscatter diffraction, and scanning and transmission electron microscopy. The transformation mechanisms change significantly with the change in sulphur content of the α-NiS phase. Massive transformation is observed for near-stoichiometric composition. For overstoichiometric composition, the transformation is controlled by a long-range diffusion mechanism. The influence of stoichiometry and impurities (Fe) on the microstructural evolution and transformation mechanisms has also been studied. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410000972 [article] Phase transformations in nickel sulphide : Microstructures and mechanisms [texte imprimé] / Oussama Yousfi, Auteur ; Patricia Donnadieu, Auteur ; Bréchet, Yves, Auteur . - 2011 . - pp. 3367–3380. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 9 (Mai 2010) . - pp. 3367–3380 Mots-clés : Nickel  sulphides  Phase  transformation  Microstructure  Massive  transformation  Diffusive  transformation Résumé : Nickel sulphide inclusions are known to be responsible for delayed fracture in tempered glasses due to phase transformation within the inclusion. Microstructural identification of the phase transformation mechanisms in the Ni–S system close to the NiS composition were carried out on a series of partially transformed states. Observations allow to investigate the morphological evolution during transformation, the phase orientation relationships and the first stages of the transformation were investigated by optical microscopy, electron backscatter diffraction, and scanning and transmission electron microscopy. The transformation mechanisms change significantly with the change in sulphur content of the α-NiS phase. Massive transformation is observed for near-stoichiometric composition. For overstoichiometric composition, the transformation is controlled by a long-range diffusion mechanism. The influence of stoichiometry and impurities (Fe) on the microstructural evolution and transformation mechanisms has also been studied. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410000972