Constrained hierarchical twinning in Ru-based high temperature shape memory alloys

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• 作者：Anna M. Manzoni^a ; ^{anna_manzoni@gmx.net" class="auth_mail" title="E-mail the corresponding author} ; Anne Denquin^a ; ^{anne.denquin@onera.fr" class="auth_mail" title="E-mail the corresponding author} ; Philippe Vermaut^b ; ^c ; ^{philippe-vermaut@chimie-paristech.fr" class="auth_mail" title="E-mail the corresponding author} ; Fré ; dé ; ric Prima^b ; ^{frederic-prima@chimie-paristech.fr" class="auth_mail" title="E-mail the corresponding author} ; Iné ; s Puente-Orench^d ; ^e ; ^{puenteorench@ill.fr" class="auth_mail" title="E-mail the corresponding author} ; Christoph Pauly^f ; ^{c.pauly@mx.uni-saarland.de" class="auth_mail" title="E-mail the corresponding author} ; Frank Mü ; cklich^f ; ^{muecke@matsci.uni-sb.de" class="auth_mail" title="E-mail the corresponding author} ; Richard A. Portier^b ; ^{richard-portier@chimie-paristech.fr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Shape memory alloys ; Transmission electron microscopy ; EBSD ; Twinning ; Ru&ndash ; Ta
• 刊名：Acta Materialia
• 出版年：2016
• 出版时间：1 June 2016
• 年：2016
• 卷：111
• 期：Complete
• 页码：283-296
• 全文大小：4677 K

文摘

The microstructure of high temperature shape memory alloys of the Ru-Ta and Ru-Nb family are investigated in detail. After cooling from the high temperature cubic β phase the off-stoichiometric alloys show a compound twinning in the tetragonal β′ phase which prevails at room temperature and can be observed as two levels of laminates A and C [1]. The stoichiometric alloys are characterized by a second phase transformation from β′ to monoclinic β″, which adds another type of twinning. The latter belongs to the monoclinic P2/m structure and has been created out of one of the lost symmetry elements from the tetragonal P4/mmm phase during the β′ → β″ transformation. The unusual characteristic of this new twinning, called B, is the fact that it has an intermediate size between the A and C twins that belong to the high-temperature transformation β′ → β″. This is due to a second constrained martensitic transformation.