Frequency Dependence of the Internal Friction for Ti50Ni48.5Fe1.5 Shape Memory Alloy

2010 ◽  
Vol 143-144 ◽  
pp. 1007-1011
Author(s):  
Ting Yong Xing ◽  
Xu Jun Mi ◽  
Xiang Qian Yin ◽  
Bao Dong Gao ◽  
Yan Feng Li
Keyword(s):  
Phase Transformation ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Internal Friction ◽  
Shape Memory ◽  
Frequency Dependence ◽  
Internal Friction Peak ◽  
Interesting Phenomenon ◽  
Measuring Frequency ◽  
Friction Measurements

The objective of this work is to investigate the influence of measuring frequency on the internal friction of Ti50Ni48.5Fe1.5 shape memory alloy. The DSC, DC electrical resistivity and internal friction measurements were employed to characterize the sample in this study. Comparing the DSC result, the two internal friction peaks were confirmed which are corresponding to the R-phase transformation and martensitic transformation of Ti50Ni48.5Fe1.5 alloy during the cooling process, respectively. The height of internal friction peak corresponding to martensitic transformation increased with decreasing of measuring frequency. But, the height of the internal friction peak corresponding to R-phase transformation exhibited little measuring frequency dependence. Meanwhile, the value of the relative modulus peaks of the specimen increased with measuring frequency increasing. Furthermore, there was an interesting phenomenon that the martensitic transformation finish temperature shifted to higher temperature side with increasing of measuring frequency. It could be associated with the variation of applied vibration energy.

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.

Effects of High Temperature ECAE Process on Microstructures and Martensitic Transformation of TiNi Shape Memory Alloy

2006 ◽  
Vol 503-504 ◽  
pp. 1013-0 ◽  
Author(s):  
Chao Ying Xie ◽  
Z.G. Fan ◽  
Z.H. Li ◽  
G.Q. Xiang ◽  
X.H. Cheng
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Tini Alloy ◽  
Behavior Changes ◽  
Transformation Behavior ◽  
Coarse Grains ◽  
Short Annealing

Microstructures and transformation behavior of TiNi shape memory alloy after high temperature ECAE process have been investigated. It is found that the initial coarse grains were refined after high temperature ECAE processes and short annealing at 750°C. Transformation temperatures of TiNi alloy sharply decreased after two ECAE processes, rose obviously when annealed at 750°C for 5min, and quickly rose back after annealing at 500°C for 2 hours. Reasons for phase transformation behavior changes have been discussed.

Effect of Ageing Temperatures on the Transformation Behaviour of Ti-50.7at.%Ni Shape Memory Alloy

2013 ◽  
Vol 845 ◽  
pp. 108-112
Author(s):  
Kurnia Hastuti ◽  
Esah Hamzah ◽  
Jasmi Hashim
Keyword(s):  
Phase Transformation ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Transformation Behaviour ◽  
Ageing Treatment

Ti-50.7at.%Ni as one of Ni-rich TiNi shape memory alloy is very responsive to precipitation ageing treatment due to the formation of Ti3Ni4 precipitates. This study indicates that this alloy exhibits different transformation sequences under different ageing temperatures. Precipitation of Ti3Ni4 has introduced the formation of intermediate R-phase prior to martensitic transformation. The lack of 2-step R-phase transformation, B2→R1 and B2→R2 transformation in this alloy, suggested that Ti3Ni4 precipitation occurs homogeneously.

Orientation Dependent Internal Friction of Textured Ti-Nb-Al Shape Memory Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 1533-1536 ◽  
Author(s):  
Y. Yamamoto ◽  
Tomonari Inamura ◽  
Kenji Wakashima ◽  
Hee Young Kim ◽  
Shuichi Miyazaki ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Internal Friction ◽  
Shape Memory ◽  
Rolling Direction ◽  
Mechanical Analysis ◽  
Martensite Phase ◽  
Tensile Direction ◽  
Heat Treated ◽  
Tan Δ

Internal friction of Ti-24mol%Nb-3mol%Al (Ti-24Nb-3Al) shape memory alloy with a well-developed texture was investigated by dynamic mechanical analysis (DMA) in a tensile mode with a frequency of 1Hz and a temperature range of 123~423K. Ti-24Nb-3Al alloy fabricated by Ar arc-melting was cold-rolled with a reduction in thickness of 99% and then heat-treated at 1173K for 3.6ks in vacuum to develop a recrystallization texture. The martensitic transformation temperature and internal friction (tan δ) were evaluated under the stress amplitude of 36MPa. The tensile direction was selected to be the rolling direction (RD) and the transverse direction (TD). The specimen was β-single phase with a well-developed {112}β<110>β texture at room temperature and exhibited high damping during martensitic transformation and in the martensite phase. The relationship between internal friction and the tensile direction is discussed on the view point of the crystallography of the transformation.

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