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Sensitivity of deformation twinning to grain size in titanium and magnesium / Alireza Ghaderi in Acta materialia, Vol. 59 N° 20 (Décembre 2011) 

Public ISBD [article]  in Acta materialia > Vol. 59 N° 20 (Décembre 2011) . - pp. 7824–7839 Titre : Sensitivity of deformation twinning to grain size in titanium and magnesium Type de document : texte imprimé Auteurs : Alireza Ghaderi, Auteur ; Matthew R. Barnett, Auteur Année de publication : 2012 Article en page(s) : pp. 7824–7839 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Twinning  Grain  size  Titanium  Magnesium Résumé : The impact of grain size on deformation twinning in commercial purity titanium and magnesium alloy Mg–3Al–1Zn (AZ31) is investigated. Tensile tests were carried out for the titanium samples; compression testing was employed for the magnesium specimens. Average values of the true twin length, true twin thickness and the number density of twins were determined using stereology. A key difference between these two materials is that twinning contributes little to the plastic strain in the titanium while it accounts for nearly all of the early plastic strain in the magnesium. In some respects (e.g. volume fraction and number density) the phenomenology of twinning differed between the two materials, while in others (e.g. twin shape and size) both materials showed a similar response. It is found that in both materials, twins span the entirety of their parent grains only for grain sizes less than ∼30 μm. Both the nucleation density per unit of nucleating interface (i.e. grain and twin boundaries) and the aspect ratio of twins scale with applied stress. The impact of grain size on twin volume fraction is modelled analytically. ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645411006550 [article] Sensitivity of deformation twinning to grain size in titanium and magnesium [texte imprimé] / Alireza Ghaderi, Auteur ; Matthew R. Barnett, Auteur . - 2012 . - pp. 7824–7839. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 59 N° 20 (Décembre 2011) . - pp. 7824–7839 Mots-clés : Twinning  Grain  size  Titanium  Magnesium Résumé : The impact of grain size on deformation twinning in commercial purity titanium and magnesium alloy Mg–3Al–1Zn (AZ31) is investigated. Tensile tests were carried out for the titanium samples; compression testing was employed for the magnesium specimens. Average values of the true twin length, true twin thickness and the number density of twins were determined using stereology. A key difference between these two materials is that twinning contributes little to the plastic strain in the titanium while it accounts for nearly all of the early plastic strain in the magnesium. In some respects (e.g. volume fraction and number density) the phenomenology of twinning differed between the two materials, while in others (e.g. twin shape and size) both materials showed a similar response. It is found that in both materials, twins span the entirety of their parent grains only for grain sizes less than ∼30 μm. Both the nucleation density per unit of nucleating interface (i.e. grain and twin boundaries) and the aspect ratio of twins scale with applied stress. The impact of grain size on twin volume fraction is modelled analytically. ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645411006550