Length scale dependent alloying and strain-rate sensitivity of TiNi multilayers》.pdfVIP

Materials Science Engineering A 648 (2015) 31–36 Contents lists available at ScienceDirect Materials Science Engineering A journal homepage: /locate/msea Length scale dependent alloying and strain-rate sensitivity of Ti/Ni multilayers J. Shi a,b, M.Z. Wei a, Y.J. Ma a, L.J. Xu a, Z.H. Cao a,n, X.K. Meng a,n a Institute of Materials Engineering, National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Nanjing University, Jiangsu, People ’s Republic of China b Department of Material Science and Engineering, East China Institute of Technology, Nanchang 330013, People ’s Republic of China a r t i c l e i n f o a b s t r a c t Article history: In this paper, we prepared alloying Ti/Ni multilayers through changing modulation periods (λ ) and Received 1 July 2015 subsequent annealing. Strain rate sensitivity of the multilayers was investigated by nanoindentation. It Received in revised form was found that the multilayer became full alloying with the highest value of hardness at λ ¼ 5.4 nm. Both 8 September 2015 the alloying degree and the corresponding hardness are remarkable dependent on λ. Only the multi- Accepted 9 September 2015 layers accompanied by obvious stress-induced pop-in events exhibit negative strain rate sensitivity re- Available online 12 September 2015 sulted from stress-induced martensitic transformation, while hardness of the other multilayers does n