In situ observation of the “crystalline⇒amorphous state” phase transformation in Ti₂NiCu upon high-pressure torsion

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• 作者：R.V. Sundeev^a ; ^{apricisvir@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; A.V. Shalimova^b ; A.M. Glezer^b ; ^c ; E.A. Pechina^d ; M.V. Gorshenkov^c ; G.I. Nosova^b
• 关键词：Severe plastic deformation ; High pressure torsion ; Amorphous materials ; Phase transformation ; Amorphization
• 刊名：Materials Science & Engineering A
• 出版年：2017
• 出版时间：2 January 2017
• 年：2017
• 卷：679
• 期：Complete
• 页码：1-6
• 全文大小：1672 K

文摘

The evolution of the structure and mechanical behavior upon deformation has been studied experimentally in situ by room-temperature high-pressure torsion (HPT) of the initially crystalline Ti₂NiCu alloy. An abrupt increase in the shear stress upon HPT has been revealed. It was found that the observed effect is due to the deformation-induced “crystalline⇒amorphous state” phase transformation and the corresponding change in the mechanism of severe plastic deformation. It is shown that the amorphization of the material begins at the boundaries of grains and fragments of the crystalline phase as a result of grain boundary sliding processes. It was established that the amorphous boundaries form a “grain-boundary framework”, which upon deformation is expanded and transformed into bulk amorphous phase.