Multiple-step martensitic transformations in the Ni51Ti49 single crystal

Multiple-step martensitic transformations of an aged Ni51Ti49 single crystal using calorimetric method were investigated. Results show that for short aging times (10–45 min) multiple-step martensitic transformations on cooling occur in two steps. Applying intermediate aging times (1.25–4 h) results in three steps and long aging times (more than 8 h) lead to two-step martensitic transformations again. This behavior has not been recognized in NiTi single crystals in literatures. It can be related to the heterogeneity of composition and stress fields around Ni4Ti3 precipitates.

[1]  Ken Gall,et al.  On the mechanical behavior of single crystal NiTi shape memory alloys and related polycrystalline phenomenon , 2001 .

[2]  Yoshiyuki Nakata,et al.  Crystal Structure, Composition and Morphology of a Precipitate in an Aged Ti-51 at%Ni Shape Memory Alloy , 1986 .

[3]  Rolf Gotthardt,et al.  Interaction between microstructure and multiple-step transformation in binary NiTi alloys using in-situ transmission electron microscopy observations , 1998 .

[4]  D. Schryvers,et al.  Quantitative determination of strain fields around Ni4Ti3 precipitates in NiTi , 2005 .

[5]  D. Schryvers,et al.  Linking a completely three-dimensional nanostrain to a structural transformation eigenstrain. , 2009, Nature materials.

[6]  Koichi Tanaka,et al.  Experimental Consideration of Multistage Martensitic Transformation and Precipitation Behavior in Aged Ni-Rich Ti-Ni Shape Memory Alloys , 2003 .

[7]  D. Schryvers,et al.  Analytical TEM investigations on concentration gradients surrounding Ni4Ti3 precipitates in Ni–Ti shape memory material , 2005 .

[8]  G. Eggeler,et al.  Direct transmission electron microscopy observations of martensitic transformations in Ni-rich NiTi single crystals during in situ cooling and straining , 2008 .

[9]  Xiaobing Ren,et al.  Origin of abnormal multi-stage martensitic transformation behavior in aged Ni-rich Ti–Ni shape memory alloys , 2004 .

[10]  G. Eggeler,et al.  Elementary martensitic transformation processes in Ni-rich NiTi single crystals with Ni4Ti3 precipitates , 2006 .

[11]  Yufeng Zheng,et al.  Effect of ageing treatment on the transformation behaviour of Ti–50.9 at.% Ni alloy , 2008 .

[12]  X. Ren,et al.  Physical metallurgy of Ti–Ni-based shape memory alloys , 2005 .

[13]  X. Ren,et al.  Understanding of multi-stage R-phase transformation in aged Ni-rich Ti–Ni shape memory alloys , 2006 .

[14]  G. Eggeler,et al.  The mechanism of multistage martensitic transformations in aged Ni-rich NiTi shape memory alloys , 2002 .

[15]  G. Eggeler,et al.  Conventional and in-situ transmission electron microscopy investigations into multistage martensitic transformations in Ni-rich NiTi shape memory alloys , 2008 .

[16]  G. Eggeler,et al.  On the effect of aging on martensitic transformations in Ni-rich NiTi shape memory alloys , 2005 .

[17]  T. Goryczka,et al.  Two-stage martensitic transformation in a deformed and annealed NiTi alloy , 1996 .

[18]  Yinong Liu,et al.  Ageing-induced two-stage R-phase transformation in Ti – 50.9at.%Ni , 2004 .

[19]  G. Eggeler,et al.  Multiple-step martensitic transformations in Ni-rich NiTi alloys--an in-situ transmission electron microscopy investigation , 2003 .

[20]  Gunther Eggeler,et al.  Ni4Ti3-precipitation during aging of NiTi shape memory alloys and its influence on martensitic phase transformations , 2002 .