Shape Memory Behavior of Ti-50.9at%Ni Alloy after ECAE Processes

2007 ◽  
Vol 561-565 ◽  
pp. 2313-2316 ◽  
Author(s):  
Zhi Guo Fan ◽  
Chao Ying Xie
Keyword(s):  
Phase Transformation ◽  
Shape Memory ◽  
Initial Solution ◽  
Transformation Behavior ◽  
Shape Memory Behavior ◽  
Solution Treated ◽  
Ni Alloy ◽  
Coarse Grains ◽  
Shape Memory Properties ◽  
Before And After

The initial coarse grains of Ti-50.9at%Ni were obviously refined after eight ECAE processes. Effects of pressing number on the transformation behavior have been investigated in detail. Comparing with the initial solution-treated Ti-50.9at%Ni, the R-phase transformation was stimulated and the martensitic temperature Ms decreased with ECAE processes at 773K. The shape memory properties of Ti-50.9at%Ni alloy before and after ECAE processes at 773K have been measured. Good one way shape memory and superelasticity were obtained for the submicron-grained Ti-50.9at%Ni alloy.

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.

scholarly journals Texture and Thermal Expansion Anomalies of B19'-Martensite in Tensile Deformed TiNi Shape Memory Alloy

1999 ◽  
Vol 32 (1-4) ◽  
pp. 71-81 ◽  
Author(s):  
V. M. Gundyrev ◽  
V. I. Zel'dovich ◽  
G. A. Sobyanina
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Solution Treated ◽  
Texture Axis ◽  
Ni Alloy ◽  
Axis Parallel ◽  
Dilatometric Studies ◽  
Strain Direction

The dilatometric studies of Ti-50.5 at.% Ni alloy have shown that the thermal expansion coefficient (TEC) of B19'-martensite varies considerably for the solution-treated and tensile-strained samples. In the undeformed state the TEC has the positive value α=9.7.10-6 K-1. After tensile straining the TEC decreases sharply and takes on a negative value (down to – 10.8.10-6 K-1). The reasons for the variation of the TEC of the B19'-phase of the solution-treated and deformed samples are discussed. The tensile straining was found to create in the samples an extremely sharp texture of the phase transformation, with the texture axis parallel to the strain direction. The TEC of monoclinic B1939;-lattice is different in various crystallographic directions and assumes a negative value in the [0 01]B19' direction.

scholarly journals Shape Memory NiTi and NiTiCu Alloys Obtained by Spark Plasma Sintering Process

2015 ◽  
Vol 13 ◽  
pp. 83-90 ◽  
Author(s):  
Cristiana Diana Cristea ◽  
Magdalena Lungu ◽  
Alexander M. Balagurov ◽  
Virgil Marinescu ◽  
Otilia Culicov ◽  
...  
Keyword(s):  
Shape Memory ◽  
Intermetallic Compounds ◽  
Spark Plasma Sintering ◽  
Sintering Process ◽  
Transformation Behavior ◽  
Plasma Sintering ◽  
New Process ◽  
Shape Memory Properties ◽  
Spark Plasma ◽  
Niti Shape Memory Alloys

The addition of Cu to near equiatomic NiTi shape memory alloys (SMAs) can provide some modifications of their shape memory properties by affecting their transformation behavior. The same effect was obtained in the case of Ni3Ti2 and Ni4Ti3 precipitates presence in the microstructure of NiTi. Also the substitution of Cu to NiTi alloys increases the hardness of the materials. This paper presents the microstructural and mechanical investigations of NiTi and NiTiCu alloys obtained by spark plasma sintering (SPS) process that represents a great potential for researchers as a new process for the fabrication of intermetallic compounds.

scholarly journals Microstructure and Phase Transformation Analysis of Ni50−xTi50Lax Shape Memory Alloys

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 345 ◽  
Author(s):  
Weiya Li ◽  
Chunwang Zhao
Keyword(s):  
Phase Transformation ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensite Transformation ◽  
Transformation Behavior ◽  
Ni Content ◽  
Start Temperature

The microstructure and martensitic transformation behavior of Ni50−xTi50Lax (x = 0.1, 0.3, 0.5, 0.7) shape memory alloys were investigated experimentally. Results show that the microstructure of Ni50−xTi50Lax alloys consists of a near-equiatomic TiNi matrix, LaNi precipitates, and Ti2Ni precipitates. With increasing La content, the amounts of LaNi and Ti2Ni precipitates demonstrate an increasing tendency. The martensitic transformation start temperature increases gradually with increasing La content. The Ni content is mainly responsible for the change in martensite transformation behavior in Ni50−xTi50Lax alloys.

scholarly journals Effect of a Small Amount of Hydrogen on Cyclic Shape Memory Behavior of Ti-Ni Alloy

1992 ◽  
Vol 56 (10) ◽  
pp. 1111-1117 ◽  
Author(s):  
Teruo Asaoka ◽  
Taisuke Kamimura ◽  
Hideo Saito ◽  
Yoichi Ishida
Keyword(s):  
Shape Memory ◽  
Shape Memory Behavior ◽  
Ni Alloy

scholarly journals Shape Memory Behavior of Carbon Black-reinforced Trans-1,4-polyisoprene and Low-density Polyethylene Composites

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 807 ◽  
Author(s):  
Lin Xia ◽  
Han Gao ◽  
Weina Bi ◽  
Wenxin Fu ◽  
Guixue Qiu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Shape Memory ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Shape Memory Behavior ◽  
Blending Method ◽  
Shape Memory Properties ◽  
Shape Memory Composites ◽  
Properties Of Composites

Shape memory composites of trans-1,4-polyisoprene (TPI) and low-density polyethylene (LDPE) with easily achievable transition temperatures were prepared by a simple physical blending method. Carbon black (CB) was introduced to improve the mechanical properties of the TPI/LDPE composites. The mechanical, cure, thermal and shape memory properties of the TPI/LDPE/CB composites were investigated in this study. In these composites, the crosslinked network generated in both the TPI and LDPE portions acted as a fixed domain, while the crystalline regions of the TPI and LDPE portions acted as a reversible domain in shape memory behavior. We found the mechanical properties of composites were promoted significantly with an increase of CB content, accompanied with the deterioration of shape memory properties of composites. When CB dosage was 5 parts per hundred of rubber composites (phr), best shape memory property of composites was obtained with a shape fixity ratio of 95.1% and a shape recovery ratio of 95.0%.

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