Effect of Rotation Speed on Transformation Behavior in Ti-48at%Ni Shape Memory Alloy Melt-Spun Ribbon

2007 ◽  
Vol 561-565 ◽  
pp. 1481-1484 ◽  
Author(s):  
Hong Yan Xing ◽  
Hee Young Kim ◽  
Shuichi Miyazaki

Effects of rotation speed on the microstructure and transformation behavior were investigated for Ti-48at%Ni melt-spun ribbons. The Ti-48at%Ni shape memory alloy ribbons were fabricated by the melt-spinning method with various rotation speeds ranging from 2500rpm to 7500rpm. The melt-spun ribbons were completely crystallized to TiNi B2 phase during solidification at lower rotation speeds less than 4000rpm. Amorphous and B2 phase coexisted in the melt-spun ribbons fabricated at higher rotation speeds of 5000rpm and 7500rpm. The martensitic transformation behavior was investigated both in the as-spun and heat-treated ribbons. The transformation temperature increased with decreasing cooling rate and increasing heat-treatment temperature.

2005 ◽  
Vol 475-479 ◽  
pp. 1925-1928 ◽  
Author(s):  
Hongyang Xing ◽  
Anak Khantachawana ◽  
Hee Young Kim ◽  
Shuichi Miyazaki

The microstructure and shape memory behavior of Ti-rich Ti-Ni melt-spun ribbons with various Ni-contents were investigated. Ti-xNi(x=40~48at%) ribbons were fabricated by the melt-spinning method at the rotation speed of 5000rpm. They were heat-treated at 1073K for 3.6ks. It was found that the Ti-40at%Ni as-spun ribbon exhibited almost complete amorphous structure, while the specimen with more Ni-content, such as 48at%Ni ribbon exhibited the coexistence of amorphous and crystalline structures. It was also found that the maximum shape recovery strain increased with increasing Ni-content. The Ti-40at%Ni ribbon was very brittle because of many Ti2Ni precipitates formed.


2005 ◽  
Vol 475-479 ◽  
pp. 2009-2012 ◽  
Author(s):  
Shi Hai Guo ◽  
Yang Huan Zhang ◽  
Bai Yun Quan ◽  
Jian Liang Li ◽  
Xin Lin Wang

A non-stoichiometric polycrystalline Ni50Mn27Ga23 magnetic shape memory alloy was prepared by melt-spinning technology. The effects of melt-spinning on the martensitic transformation and magnetic-field-induced strain (MFIS) of the melt-spun ribbon were investigated. The experimental results show that the melt-spun ribbon undergoes the thermal-elastic martensitic transformation and exhibits the thermo-elastic shape memory effect. But the martensitic transformation temperature decreases and Curie temperature remains unchanged. A particular internal stress induced by melt-spinning made a texture structure in the melt-spun ribbon, which made the melt-spun ribbon obtain larger transition-induced strain and MFIS. The internal stress was released under cycling of magnetic field. This resulted in a decrease of MFIS of the melt-spun ribbon.


2013 ◽  
Vol 738-739 ◽  
pp. 352-356 ◽  
Author(s):  
Alexander Shelyakov ◽  
Nikolay Sitnikov ◽  
Sergey Saakyan ◽  
Alexey Menushenkov ◽  
Razhudin Rizakhanov ◽  
...  

Recently we reported on the development of a composite material exhibiting reversible shape memory effect. A Ti–25Ni–25Cu (at.%) alloy was obtained by the melt spinning technique as amorphous–crystalline ribbons with a thickness of approximately 40 μm. The thickness of the amorphous and crystalline layers (dа and dc, respectively) was varied by electrochemical polishing. It has been ascertained that with varying the relationship dc/dа the martensite transformation and shape-recovery temperatures do not actually change, while the minimum radius of the ribbon bending decreases from 8.0 mm to 2.4 mm with increasing the relationship dc/dа from 0.33 to 1.40. The maximum reversible strain comprises 0.4% at dc/dа = 0.82. On the basis of experimental data obtained the phenomenological description, providing an explanation for nature of the phenomena taking place in the rapidly quenched amorphous-crystalline ribbon composite, has been proposed.


2009 ◽  
Vol 18 (7) ◽  
pp. 3031-3034 ◽  
Author(s):  
Meng Fan-Bin ◽  
Guo Hong-Jun ◽  
Liu Guo-Dong ◽  
Liu He-Yan ◽  
Dai Xue-Fang ◽  
...  

2016 ◽  
Vol 879 ◽  
pp. 256-261 ◽  
Author(s):  
Taywin Buasri ◽  
Hyun Bo Shim ◽  
Masaki Tahara ◽  
Tomonari Inamura ◽  
Kenji Goto ◽  
...  

Phase constitution and martensitic transformation behavior were investigated for a Au–51Ti–18Co alloy heat-treated at 1173 K to 1373 K for 3.6 ks. The Au–51Ti–18Co alloy was fabricated by Ar arc-melting technique and subsequently by hot-forging at 1423 K for 10.8 ks. X-ray diffraction analysis revealed that B2 parent phase, B19 martensite phase and AuTi3 simultaneously appeared regardless of the heat-treatment temperatures. By increasing the heat-treatment temperature, the volume fraction of AuTi3 was slightly reduced. Besides, the lattice transformation strain which was calculated from the precisely-determined lattice parameters was evaluated to be 7 % in the Au–51Ti–18Co alloy in all the heat-treated conditions. This value is comparable to that of NiTi practical alloys. From differential scanning calorimetry (DSC) analysis, reverse martensitic transformation temperature was slightly increased with the heat-treatment temperature. From the lattice transformation strain point of views, the Au–51Ti–18Co has a large potential for novel biomedical shape memory alloy.


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