Shape Memory Behavior of Porous NiTi Alloy

2016 ◽  
Vol 47 (4) ◽  
pp. 1499-1503 ◽  
Author(s):  
Mehmet Kaya ◽  
Ömer Çakmak
2007 ◽  
Vol 359-360 ◽  
pp. 143-147
Author(s):  
Yi Yi Tao ◽  
Jiu Hua Xu ◽  
Wen Feng Ding

The machining performance of porous NiTi shape memory alloys prepared using powder metallurgical production technique has been investigated experimentally in the grinding operation. Grinding force ratio, specific grinding energy, surface characteristics were detected. The result reveals that, much difference of grinding characteristics exists among three kinds of NiTi alloy because of the pore rate and the mechanical performance induced by TiH2. Under the experimental conditions, the integrated effects of predominant plastic flow and slight brittle fracture were taken for porous NiTi alloy during grinding. Additionally, the grinding parameters should be chosen carefully, otherwise the surface quality deteriorates and even the microcrack perhaps appears.


2010 ◽  
Vol 97-101 ◽  
pp. 1083-1086
Author(s):  
Hai Chang Jiang ◽  
Shu Wei Liu ◽  
Xiu Yan Li ◽  
Li Jian Rong

One internal friction peak associated with the B2↔B19’ transformation appears on the cooling curve of porous NiTi shape memory alloy and the dense NiTi alloy shows the maximum peak. The tan δ value increased with the increasing of strain amplitude and the decreasing of frequency. Tan δ value of porous alloy mainly comes from the energy absorbing of the matrix at the small strain amplitude, however, if the strain amplitude is large, the tan δ value comes from the energy consumption that overcomes the friction between folds and the plastic contribution.


2012 ◽  
Vol 21 (10) ◽  
pp. 105013 ◽  
Author(s):  
Young Ik Yoo ◽  
Dong Kil Shin ◽  
Chang Ho Lee ◽  
Jung Ju Lee

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2410-2416
Author(s):  
H. C. JIANG ◽  
Y. CHEN ◽  
S. W. LIU ◽  
L. J. RONG

The pore characteristics and pore size distribution of porous near-equiatomic NiTi shape memory alloy fabricated by self-propagating high-temperature synthesis (SHS) are described in detail. The effects of different heat treatments on the transformation of porous NiTi alloy were investigated by differential scanning calorimetry (DSC), x-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicate that heat treatment had strong influences on the transformation temperatures and latent heats of transformation. When the porous alloy was annealed at 648K and 748K for 3.6ks, two steps transformation including R transformation occurred during cooling and heating and the R transformation temperatures are lower than B 2↔ B 19' transformation temperatures. However, no transformation was detected within the experimental temperature range if the porous alloy was solution treated at 1133K for 2.4ks. This novel phenomenon was the results of extensive Ti2Ni intermetallic compound precipitation. The transformation temperatures of porous NiTi alloy after annealing at 1323K for 3.6ks were much lower than those of the untreated alloy.


2008 ◽  
Vol 56 (13) ◽  
pp. 3266-3277 ◽  
Author(s):  
Kiyohide Wada ◽  
Yong Liu

2021 ◽  
Vol 11 (4) ◽  
pp. 1802
Author(s):  
Sneha Samal ◽  
Orsolya Molnárová ◽  
Filip Průša ◽  
Jaromír Kopeček ◽  
Luděk Heller ◽  
...  

An analysis of the shape memory effect of a NiTi alloy by using the spark plasma sintering approach has been carried out. Spark plasma sintering of Ti50Ni50 powder (20–63 µm) at a temperature of 900 °C produced specimens showing good shape memory effects. However, the sample showed 2.5% porosity due to a load of 48 MPa. Furthermore, an apparent shape memory effect was recorded and the specimens were characterized by uniformity in chemical composition and shape memory alloys of NiTi showed significant austenite phases with a bending strain recovery of >2.5%.


Author(s):  
Eva Sanchez-Rexach ◽  
Patrick T. Smith ◽  
Alvaro Gomez-Lopez ◽  
Maxence Fernandez ◽  
Aitziber L. Cortajarena ◽  
...  

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