Issue
J. Phys. IV France
Volume 112, October 2003
Page(s) 769 - 772
DOI https://doi.org/10.1051/jp4:2003995


J. Phys. IV France
112 (2003) 769
DOI: 10.1051/jp4:2003995

In situ TEM study of the shape recovery process in predeformed NiTi shape memory alloy

Z. Xie1, Y. Liu2 and E. Stach3

1  School of Materials Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798
2  School of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798
3  The National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Califomia, U.S.A.


Abstract
Shape recovery of pre-deformed martensitic NiTi shape memory alloy was studied by TEM during insitu heating up to 300°C, a temperature significantly higher than the $A_{\rm f}$ temperature of the same material in bulk. Special attention has been paid to the microstructure variation upon subsequent heating and cooling. It is found that, although both forward and reverse phase transformations have taken place, the morphology of pre-deformed microstructure remains unchanged. The subsequently formed martensite upon re-cooling to room temperature consists of no lattice twins.



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