Size dependent strain rate sensitivity transition from positive to negative in Ti/Ni multilayers

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• 作者：J. Shi^a ; ^b ; ^{jshi_ecit@163.com} ; Z.H. Cao^b ; ^{caozhenhua@nju.edu.cn} ; J.G. Zheng^a
• 关键词：Ti/Ni multilayers ; Nanoindentation ; Interface ; Strain rate sensitivity
• 刊名：Materials Science and Engineering: A
• 出版年：2017
• 出版时间：5 January 2017
• 年：2017
• 卷：680
• 期：Complete
• 页码：210-213
• 全文大小：932 K
• 卷排序：680

文摘

This work presents a length scale dependent strain rate sensitivity (SRS) transition from positive to negative in Ti/Ni multilayers with unequal thickness of individual layer. The multilayers exhibit distinct interfacial structure and no Ti-Ni amorphous intermixed layer between Ni and Ti layers. It can be found that the hardness first increases with strain rate at large modulation period (λ), showing a positive SRS. Subsequently, a tunable (positive to negative) size dependent SRS phenomenon occurs with further decrease of λ. The present negative SRS is attributed to deterioration of the plasticity with decreasing λ and at larger strain rate, which induces microcracks formation.