INFLUENCE OF POROSITY ON SHAPE MEMORY BEHAVIOR OF POROUS TiNi SHAPE MEMORY ALLOY

2008 ◽  
Vol 01 (03) ◽  
pp. 215-219 ◽  
Author(s):  
JIANYU XIONG ◽  
YUNCANG LI ◽  
PETER D. HODGSON ◽  
CUI'E WEN
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Tini Alloy ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
Recoverable Strain ◽  
Strain Concentration ◽  
X Ray ◽  
Shape Memory Behavior ◽  
Porous Ti

Porous Ti -50.5at.% Ni shape memory alloy (SMA) samples with a range of porosities were prepared by spacer sintering. The porous structure of the alloy was examined using scanning electron microscopy (SEM). The phase constituents of the porous TiNi alloy were determined by X-ray diffraction (XRD). The shape memory behavior of the porous TiNi alloy was investigated using loading–unloading compression tests. Results indicate that the porous TiNi alloy exhibits superelasticity and the recoverable strain by the superelasticity decreases with the increase of porosity. After a prestrain of 7%, the superelastically recovered strains for the porous TiNi alloy samples with porosities of 46%, 59%, 69% and 77% are 2.0%, 1.8%, 1.5% and 1.3%, respectively. The pores in the TiNi alloy samples cause stress/strain concentration, as well as crack initiation, which adversely affect the shape memory behavior of the porous TiNi alloy.

scholarly journals Nanocrystal, phase transformation and microstructure of Ni50Ti50 shape memory alloy

2018 ◽  
Vol 24 (02) ◽  
pp. 22-25
Author(s):  
Dovchinvanchig M ◽  
Chunwang Zhao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
One Step ◽  
Niti Matrix ◽  
Electronic Microscope

The nanocrystal, phase transformation and microstructure behavior of Ni50Ti50 shape memory alloy was investigated by scanning electronic microscope, X-ray diffraction and differential scanning calorimetry. The results showed that the microstructure of Ni-Ti binary alloy consists of the NiTi2 phase and the NiTi matrix phase. One-step phase transformation was observed alloy.

Evaluation of the Mechanical Properties of Glass/Epoxy Composite by Embedding Shape Memory Alloy and Nanoclay

2021 ◽  
Vol 1019 ◽  
pp. 3-11
Author(s):  
Niranjan Pattar ◽  
S.F. Patil ◽  
Pratik Patil ◽  
Iranna Anikivi ◽  
Shridhar Hiremath
Keyword(s):  
Electron Microscopy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Smart Materials ◽  
Epoxy Composite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Clay Concentration ◽  
Impact Characteristics

Embedding smart materials in the composite to enhance mechanical strength have become a research hotspot owing to their unique properties. The present research also focus on novel way to fabricate composite by embedding Shape Memory Alloy (SMA) wire and montmorillonite (MMT) nanoclay by varying clay concentration (0-7 wt.%). The extent of dispersion of nanoclay in epoxy resin was studied using Transmission Electron Microscopy (TEM) and X-ray diffraction (XRD). Fabricated samples were examined for tensile, flexural and impact characteristics. Scanning Electron Microscopy (SEM) was used to study the adhesion, delamination and damage occurred within the composite due to tensile loading. Results shows that the tensile strength, flexural strength and impact energy of SMA/MMT/glass/epoxy composite was improved by 23%, 21% and 57% respectively, when it was compared with composite with glass/epoxy composite.

scholarly journals Study of CuAlBe Shape Memory Alloy by X-Ray Diffraction

1995 ◽  
Vol 05 (C2) ◽  
pp. C2-269-C2-274 ◽  
Author(s):  
F. Moreau ◽  
A. Tidu ◽  
Ph. Barbe ◽  
A. Eberhardt ◽  
J. J. Heizmann
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
X Ray Diffraction ◽  
X Ray

409 Crystal Structure of Ti-Ni Shape Memory Alloy : Part I ; X-ray Diffraction of Ti and Ni

2001 ◽  
Vol 2001 (0) ◽  
pp. 373-374
Author(s):  
Hajime KAYANO ◽  
Mitsuo NOUTOMI ◽  
Hisao HASEGAWA ◽  
Haruo SHIMOSAKA ◽  
Noburou EHARA
Keyword(s):  
Crystal Structure ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alloy Part

Phase Transformation in Ti-Ni-Ta Shape Memory Alloy

2007 ◽  
Vol 130 ◽  
pp. 147-150 ◽  
Author(s):  
Zdzisław Lekston ◽  
Tomasz Goryczka
Keyword(s):  
Phase Transformation ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Medical Application ◽  
Precipitation Process ◽  
X Ray Diffraction ◽  
Martensitic Transformation Temperature ◽  
X Ray ◽  
Solution Treated

A new Ti50Ni48.7Ta1.3 shape memory alloy was designed for medical application. In order to influence the martensitic transformation temperature the alloy was solution treated and additionally aged at 400oC for various time. Phase transformation was studied applying differential scanning calorimeter (DSC) and X-ray diffraction techniques. The ageing causes that the martensitic transformation occurs in two steps: B2↔R↔B19’ during cooling and heating. During cooling the transformations: B2→R and R→B19’ are well separated whereas on heating they are overlapped. Also ageing causes a shift of temperatures of the martensitic transformation into the higher region. It is due to the precipitation process. Precipitates of the Ni4Ti3 phase were observed. Applied thermal treatment leads to shift of the transformation temperatures below temperature of a human body. This makes the Ti-Ni-Ta alloy attractive for application in medicine.

Hrem Studies of Rapidly Solidified Ni-Fe-Al-B Shape Memory Alloys.

1991 ◽  
Vol 246 ◽  
Author(s):  
R. Pērez ◽  
J. A. Juārez-Islas ◽  
P. Johansson ◽  
M. Wallin ◽  
S. J. Savage
Keyword(s):  
Shape Memory ◽  
Martensite Transformation ◽  
Melt Spinning ◽  
Image Contrast ◽  
X Ray Diffraction ◽  
Recoverable Strain ◽  
X Ray ◽  
Atomic Structures ◽  
Wide Range ◽  
Rapidly Solidified

AbstractA series of (NixFeyAlz)0.9983B0.0017 (where x=58-60, y=13-15 and z=26-28, in at%) alloys have been rapidly solidified by - melt spinning. The ribbons have been characterized by HREM, DSC, X-ray diffraction and recoverable strain measurements. The as-cast alloys exhibit excellent bend ductility (in contrast to B2 type alloys conventionally cast) and a wide range of transformation temperatures: Ms=244-466 K, Mf=200-395K, As=236-427K and Af=262-526K. X-ray diffraction shows the presence of β (NiAl), β′ (NiAl), γ (Ni3Al), γ′ (Ni3A1), Ni and other phases such as Fe3Al, FeAl, FeNi and Al5Fe2. It is the β- β′ diffusionless transformation which is responsible for the shape memory effect. The results obtained by transmission electron microscopy (TEM) show two different types of crystalline grains. In one case, the grains have a high density of twins which are the fingerprints of the martensite transformation. However, other areas in the specimen show crystalline grains with very poor image contrast due to the transformation from β′ -β. There are also sections in the specimens with domains of both crystalline sgrains in coexistance. Both crystalline grains have large amounts of precipitates. In the β′ (NiAl) phase the size of the precipitates range fron lnm to lOnm. In the γ (Ni3Al) phase large precipitates (20nm) can be found. Some of them display pentagonal shapes which resemble the image contrast obtained in the TEM for small icosahedral metallic particles. Experimental evidence is also obtained on different habit or twin planes. HREM images from the twinned areas suggest diferent kinds of atomic structures for the parent and martensite crystalline sections. These results give some insights into the nature of the martensite transformation.

scholarly journals Crystallograply of Ni-Ti Shape Memory Alloy by X-Ray Diffraction and Diffraction Pattern Simulation

2005 ◽  
Vol 54 (6) ◽  
pp. 601-606 ◽  
Author(s):  
Mitsuo NOTOMI ◽  
Hajime KAYANO ◽  
Hisao HASEGAWA ◽  
Haruo SHIMOSAKA ◽  
Noburo EHARA
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Diffraction Pattern ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pattern Simulation
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