The determination of the influence of heat treatment on the martensitic transformation in Cu-Zn-Al-Mn shape-memory alloy by calorimetry and acoustic emission techniques

1992 ◽  
Vol 205 ◽  
pp. 75-85 ◽  
Author(s):  
F.J. Gil ◽  
J.M. Guilemany
Keyword(s):  
Heat Treatment ◽  
Acoustic Emission ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory

scholarly journals Effect of Heat Treatment Temperature on Martensitic Transformation and Superelasticity of the Ti49Ni51 Shape Memory Alloy

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2539 ◽  
Author(s):  
Peiyou Li ◽  
Yongshan Wang ◽  
Fanying Meng ◽  
Le Cao ◽  
Zhirong He
Keyword(s):  
Heat Treatment ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Thermal Hysteresis ◽  
Treatment Temperature ◽  
Heat Treated ◽  
Different Temperatures ◽  
Tini Phase ◽  
Rapidly Solidified

The martensitic transformation and superelasticity of Ti49Ni51 shape memory alloy heat-treatment at different temperatures were investigated. The experimental results show that the microstructures of as-cast and heat-treated (723 K) Ni-rich Ti49Ni51 samples prepared by rapidly-solidified technology are composed of B2 TiNi phase, and Ti3Ni4 and Ti2Ni phases; the microstructures of heat-treated Ti49Ni51 samples at 773 and 823 K are composed of B2 TiNi phase, and of B2 TiNi and Ti2Ni phases, respectively. The martensitic transformation of as-cast Ti49Ni51 alloy is three-stage, A→R→M1 and R→M2 transformation during cooling, and two-stage, M→R→A transformation during heating. The transformations of the heat-treated Ti49Ni51 samples at 723 and 823 K are the A↔R↔M/A↔M transformation during cooling/heating, respectively. For the heat-treated alloy at 773 K, the transformations are the A→R/M→R→A during cooling/heating, respectively. For the heat-treated alloy at 773 K, only a small thermal hysteresis is suitable for sensor devices. The stable σmax values of 723 and 773 K heat-treated samples with a large Wd value exhibit high safety in application. The 773 and 823 K heat-treated samples have large stable strain–energy densities, and are a good superelastic alloy. The experimental data obtained provide a valuable reference for the industrial application of rapidly-solidified casting and heat-treated Ti49Ni51 alloy.

scholarly journals Acoustic Emission as a Probe of the Kinetics of the Martensitic Transformation in a Shape Memory Alloy

2006 ◽  
Vol 47 (3) ◽  
pp. 607-611 ◽  
Author(s):  
Stefanus Matheus Cornelis van Bohemen ◽  
Jilt Sietsma ◽  
Roumen Petrov ◽  
Marcel Joseph Marie Hermans ◽  
Ian Malcom Richardson
Keyword(s):  
Acoustic Emission ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Kinetics Of

Effect of Repeated Heat-Treatment under Constrained Strain on Mechanical Properties of Ti-Ni Shape Memory Alloy

2012 ◽  
Vol 78 ◽  
pp. 69-74
Author(s):  
Hiroki Cho ◽  
Takaei Yamamoto ◽  
Akihiko Suzuki ◽  
Toshio Sakuma ◽  
Kiyoshi Yamauchi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Breaking Strength ◽  
Applied Strain ◽  
Shape Memory Alloy Wire ◽  
Breaking Strain ◽  
Alloy Wire

It is well-known that the Ti-Ni shape memory alloy (SMA) is applicable to the medical stent. The repeated heat-treatment under the constrained strain is necessary for the manufacturing process of the laser-cut SMA stent. In this research, the effect of heat-treatment under the constrained strain on mechanical properties of the Ti-Ni shape memory alloy wire was investigated. The applied strain at single heat-treatment (εap) was 4, 5 and 8%, and the heat-treatment is repeated so as to became total applied strain 40%. In the case of εap=4 and 5%, partial transformation occurs in the SMA wire, and so a necking appears in the SMA wire. Due to this necking, multi-step martensitic transformation, and decreasing of breaking strength / breaking strain are caused. The necking does not occur because the whole of the SMA wire is transformed for εap=8%. The mechanical properties are improved by increasing of εap. Nevertheless, the mechanical properties of each sample are inappropriate for the medical stent. However, the mechanical properties of the as-manufactured sample are improved greatly by training. In addition, it is desirable that the applied strain during training is slightly larger than the requested strain for application.

Phase Constitution and Martensitic Transformation Behavior of Au-51Ti-18Co Biomedical Shape Memory Alloy Heat-Treated at 1173K to 1373K

2016 ◽  
Vol 879 ◽  
pp. 256-261 ◽  
Author(s):  
Taywin Buasri ◽  
Hyun Bo Shim ◽  
Masaki Tahara ◽  
Tomonari Inamura ◽  
Kenji Goto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Heat Treatment Temperature ◽  
Transformation Strain ◽  
Treatment Temperature ◽  
Transformation Behavior ◽  
Heat Treated ◽  
Alloy Heat

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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