On the tetragonality of martensites in ferrous shape memory alloy Fe₃Pt: A first-principles study

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• 作者：Song Lu^a ; ^b ; ^{lusommmg@hotmail.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Ferrous shape memory alloy ; Bain path ; Fe3Pt ; First-principles
• 刊名：Acta Materialia
• 出版年：2016
• 出版时间：1 June 2016
• 年：2016
• 卷：111
• 期：Complete
• 页码：56-65
• 全文大小：811 K

文摘

First-principles calculations have been performed to study the effects of point defects on the tetragonality of martensites in ferrous shape memory alloy Fe₃Pt. By computing the Bain path, I show that by considering point defects, all the face-centered cubic (fct) and body-centered cubic (bct) phases with c/a values close to the experimental observations are predicted. Atomic structure analysis gives evidence about the proposed “antiferrodistortive transformation” which was previously derived from the softened phonon mode of Fe₃Pt. We discuss the dependence of the Bain path on the concentration of defects and show that the observed bct structures are closely related to the particular shape of the L1₂ Bain path. Magnetism is identified as the origin of the extremely flat Bain path. The role of the enhanced band Jahn-Teller effect in stabilizing the fct phases is discussed.