Elastic behavior during early stage of β phase decomposition in a Cu–Al–Ni shape memory alloy

TiNi shape memory alloy thin sheets were produced from titanium and nickel metal sheets by a new processing consisting of repetitive roll-bonding and diffusional heat treatment. TiNi sheets after heat treatment at a relatively low temperature for a long time exhibited fairly isotropic and high shape-recoverable strain, because a near {111} B2-phase texture such as {223}<110> and {332}<113> was developed through reactive diffusion during heat treatment. In the early stage of reactive diffusion, intermetallic layers of Ti2Ni, TiNi and Ni3Ti were formed at once at the Ti/Ni interfaces of the roll-bonded laminate and then growth of a TiNi phase took place with the progress of interdiffusion. Texture of the final TiNi thin sheets, therefore, is derived from that of TiNi layers generated at the Ti/Ni interfaces, which is considered to have inherited rolling textures of Ni and Ti layers in the Ti/Ni laminate prior to reactive diffusion under orientation relationships on close-packed plane and direction between parent and product phases.

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Determination of Preferred Morphology of Self-Accommodating Martensite in Ti-Nb-Al Shape Memory Alloy Using Optical Microscopy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.922.260 ◽

2014 ◽

Vol 922 ◽

pp. 260-263 ◽

Cited By ~ 1

Author(s):

Masatoshi Ii ◽

Masaki Tahara ◽

Hideki Hosoda ◽

Shuichi Miyazaki ◽

Tomonari Inamura

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Optical Microscopy ◽

Early Stage ◽

Type I ◽

Type Ii ◽

Different Types ◽

Forward Transformation

The preferred morphology of self-accommodation (SA) microstructure in a Ti-Nb-Al shape memory alloy was investigated by the evaluation of the frequency distribution of the habit plane variant (HPV) clusters using in-situ optical microscopy. The observed HPV clusters were classified into two different types; one is the cluster connected by the {111}o type I twin (Type I) and the other is connected by the <211>o type II twin (Type II). The total fractions of the Type I and Type II clusters were 52% and 48%, respectively. The incompatibility at junction planes (JPs) of the two clusters was almost the same among these clusters. However, most of the larger martensite plates (> 50μm) formed Type I cluster at the later stage of the reverse martensitic transformation, i.e., at the early stage of the forward transformation upon cooling. The ratio of the fraction of Type I and II is almost 2:1 at the early stage of the forward transformation.

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Phase decomposition in a β Cu–Zn–Al–Ti–B shape memory alloy

Materials Science and Engineering A ◽

10.1016/j.msea.2004.10.015 ◽

2005 ◽

Vol 392 (1-2) ◽

pp. 386-393 ◽

Cited By ~ 9

Author(s):

A.M. Furlani ◽

M. Stipcich ◽

R. Romero

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Phase Decomposition

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HRTEM Observation of β’-Phase in Cu-40.26 at.% Zn Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.2305 ◽

2007 ◽

Vol 561-565 ◽

pp. 2305-2308

Author(s):

Masaaki Nishiyama ◽

Daisuke Hamatani ◽

Kenji Matsuda ◽

Tokimasa Kawabata ◽

Yasuhiro Uetani ◽

...

Keyword(s):

Crystal Structure ◽

Early Stage ◽

Phase Decomposition ◽

Hrtem Image ◽

Β Phase ◽

Transmission Electron ◽

Hrtem Observation ◽

The Matrix ◽

Cscl Structure ◽

Zn Alloy

There have been many reports about the bainitic phase decomposition of annealed Cu-Zn alloy. During annealing at 523 K, the hardness of this alloy increased at the early stage of annealing, although the β-phase couldn't be observed in the matrix of β'-phase (CsCl). The crystal structure of β' phase, thus, was investigated by a high-resolution transmission electron microscopy (HRTEM) to find its structural change. As the result, the striations were observed in the HRTEM image of matrix at the early stage of annealing. The selected area diffraction pattern was also obtained from this area, and it showed the extra streaks which couldn't be explained by the normal CsCl structure of the β’-phase.

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Super-Elastic Behavior Analysis of Shape Memory Alloy Vascular Stent

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.725.405 ◽

2016 ◽

Vol 725 ◽

pp. 405-409 ◽

Cited By ~ 1

Author(s):

Liang Tao ◽

Chang Luo ◽

Wei Xuan Li ◽

Yao Jiang Zhang

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Mechanical Model ◽

Elastic Behavior ◽

Niti Shape Memory Alloy ◽

Analysis Model ◽

Vascular Stent ◽

Free Expansion ◽

Deformation Equation ◽

Nonlinear Mechanical

NiTi shape memory alloy (SMA) vascular stent, with good bio-compatibility and super-elastic properties, has become an important medical device in clinical treatment of cardiovascular or cerebrovascular diseases. The free expansion of stent in vessel involves the mechanical behavior of geometric large deformation related to the structure of super-elastic. In this paper, the nonlinear mechanical model for the substructure of NiTi shape memory alloy vascular stent is established, and the displacement deformation equation is derived. The geometric non-linearity of the structure is proved. Furthermore, the geometric nonlinear mechanical model is verified by numerical method. The mechanical analysis model of NiTi shape memory alloy vascular stent is widely used in the field of tracheal stent and so on.

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β-Phase thermal degradation in Zr-added Cu–Zn–Al shape memory alloy

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-017-6157-z ◽

2017 ◽

Vol 129 (1) ◽

pp. 201-207 ◽

Cited By ~ 4

Author(s):

Marcelo Stipcich ◽

Ricardo Romero

Keyword(s):

Shape Memory Alloy ◽

Thermal Degradation ◽

Shape Memory ◽

Β Phase

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