Phase transformation and viscoplasticity coupling in polycrystalline nickel-titanium-hafnium high-temperature shape memory alloys

2021 ◽  
pp. 117381
Author(s):  
Pawan S. Chaugule ◽  
Othmane Benafan ◽  
Jean-Briac le Graverend
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Nickel Titanium ◽  
Polycrystalline Nickel

Quantitative Texture Analysis and Phase Fraction of Nickel-Titanium Shape Memory Alloys by Means of Neutron Diffraction

2004 ◽  
Vol 443-444 ◽  
pp. 267-270 ◽  
Author(s):  
H. Sitepu ◽  
Heinz Günter Brokmeier
Keyword(s):  
Neutron Diffraction ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Orientation Distribution ◽  
Nickel Titanium ◽  
Phase Fraction ◽  
Polycrystalline Nickel ◽  
Minor Variation ◽  
Pole Figures ◽  
Niti Shape Memory Alloys

The orientation distribution function (ODF) of the textured polycrystalline nickel titanium (NiTi) shape memory alloys (SMAs) was determined from the measured austenitic (B2)pole-figures by neutron diffraction. The texture results showed that neutron diffraction is an excellent tool to investigate the minor variation in the texture of NiTi alloys, which is very sensitive to the variation of the content of nickel in the materials. Moreover, the alloys crystallographic phase fraction and texture were calculated from Rietveld refinement with generalized spherical harmonic (GSH) description for the measured complete neutron powder diffraction (ND) spectrum, rather than a few isolated peaks, during in-situ temperature-induced martensitic transformation. The phase fraction results are consistent with the differential scanning calorimeter (DSC) curves.

Phase transformation and microstructure of quaternary TiNiHfCu high temperature shape memory alloys

2005 ◽  
Vol 13 (2) ◽  
pp. 197-201 ◽  
Author(s):  
X.L. Meng ◽  
W. Cai ◽  
K.T. Lau ◽  
L.C. Zhao ◽  
L.M. Zhou
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory

Evolutions of Microstructure and Phase Transformation in Cu-Al-Fe-Nb/Ta High-Temperature Shape Memory Alloys

2015 ◽  
Vol 833 ◽  
pp. 67-70
Author(s):  
Shui Yuan Yang ◽  
Cui Ping Wang ◽  
Yu Su ◽  
Xing Jun Liu
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Transformation Behavior ◽  
Two Phase ◽  
Phase Transformation Behavior ◽  
Three Phase

The evolutions of microstructure and phase transformation behavior of Cu-Al-Fe-Nb/Ta high-temperature shape memory alloys under the quenched and aged states were investigated in this study, including Cu-10wt.% Al-6wt.% Fe, Cu-10wt.% Al-4wt.% Fe-2wt.% Nb and Cu-10wt.% Al-4wt.% Fe-2wt.% Ta three types alloys. The obtained results show that after quenching, Cu-10wt.% Al-6wt.% Fe alloy exhibits two-phase microstructure of β′1 martensite + Fe (Al,Cu) phase; Cu-10wt.% Al-4wt.% Fe-2wt.% Nb alloy also has two-phase microstructure of (β′1 + γ′1 martensites) + Nb (Fe,Al,Cu)2 phase; Cu-10wt.% Al-4wt.% Fe-2wt.% Ta alloy is consisted of three-phase of (β′1 + γ′1 martensites) + Fe (Al,Cu,Ta) + Ta2(Al,Cu,Fe)3 phases. However, α (Cu) phase precipitates after aging for three alloys; and Fe (Al,Cu,Nb) phase is also present in Cu-10wt.% Al-4wt.% Fe-2wt.% Nb alloy. All the studied alloys exhibit complicated martensitic transformation behaviors resulted from the existence of two types martensites (β′1 and γ′1).

scholarly journals Cyclic degradation of titanium–tantalum high-temperature shape memory alloys — the role of dislocation activity and chemical decomposition

2015 ◽  
Vol 08 (06) ◽  
pp. 1550062 ◽  
Author(s):  
T. Niendorf ◽  
P. Krooß ◽  
C. Somsen ◽  
R. Rynko ◽  
A. Paulsen ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Elevated Temperatures ◽  
Nickel Titanium ◽  
Chemical Decomposition ◽  
Ω Phase ◽  
The Matrix ◽  
Cyclic Degradation

Titanium–tantalum shape memory alloys (SMAs) are promising candidates for actuator applications at elevated temperatures. They may even succeed in substituting ternary nickel–titanium high temperature SMAs, which are either extremely expensive or difficult to form. However, titanium–tantalum alloys show rapid functional and structural degradation under cyclic thermo-mechanical loading. The current work reveals that degradation is not only governed by the evolution of the ω-phase. Dislocation processes and chemical decomposition of the matrix at grain boundaries also play a major role.

scholarly journals Phase transformation volume amplitude as a low-cycle fatigue indicator in nickel–titanium shape memory alloys

2020 ◽  
Vol 178 ◽  
pp. 442-446 ◽  
Author(s):  
Harshad M. Paranjape ◽  
Bill Ng ◽  
Ich Ong ◽  
Lot Vien ◽  
Christopher Huntley
Keyword(s):  
Phase Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Low Cycle Fatigue ◽  
Nickel Titanium ◽  
Cycle Fatigue

scholarly journals Characterization Techniques of a Shape Memory Nickel Titanium Alloy

Proceedings ◽  
2020 ◽  
Vol 38 (1) ◽  
pp. 15
Author(s):  
Andrade ◽  
Soares ◽  
Nobrega ◽  
Hilário ◽  
Santos
Keyword(s):  
Differential Scanning Calorimetry ◽  
Titanium Alloy ◽  
Phase Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Tensile Tests ◽  
Metallic Alloys ◽  
Nickel Titanium ◽  
Metallographic Analysis ◽  
Scanning Calorimetry

This paper presents a characterization processes study of metallic alloys, more specifically the shape memory alloys (SMA) composed by Nickel and Titanium (NiTinol). Two different wire suppliers were studied, starting with metallographic analysis until observe the contours of the grain wires. Differential scanning calorimetry (DSC) test was also performed to obtain phase transformation temperatures of the NiTinol alloys. Finally, after several tensile tests, some results were obtained for stresses, strains, elasticity modules and maximum rupture deformation.

Microstructure and Phase Transformation Behavior of Ni-Mn-Fe High-Temperature Shape Memory Alloys

2015 ◽  
Vol 833 ◽  
pp. 63-66
Author(s):  
Cui Ping Wang ◽  
Yu Ding Liu ◽  
Shui Yuan Yang ◽  
Xing Jun Liu
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Transformation Behavior ◽  
Phase Transformation Behavior ◽  
Heating And Cooling ◽  
High Transformation ◽  
Irreversible Phase Transformation ◽  
Very High

The microstructure and phase transformation behavior of Ni-Mn-Fe high-temperature shape memory alloys including Ni40+xFe10Mn50-x (x = 0, 10) were investigated. The results show that both two alloys exhibit single fcc γ phase annealed at 900°C for 1 day. When these quenched alloys are again annealed at 500°C for 20 days, they almost exhibit main tetragonal θ martensite. The microstructural evolutions are consistent with the results of phase transformation measurements. It is clearly found that there is an irreversible phase transformation around 480°C ~ 570°C, which is associated with the formation of tetragonal θ martensite from γ phase. Afterwards, the reversible martensitic transformation occurs during heating and cooling with very high transformation temperature.

High-Temperature Shape Memory Alloys Based on Ti-Platinum Group Metals Compounds

2014 ◽  
Vol 783-786 ◽  
pp. 2541-2545 ◽  
Author(s):  
Yoko Yamabe-Mitarai ◽  
Abdul Wadood ◽  
Raju Arockiakumar ◽  
Toru Hara ◽  
Madoka Takahashi ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Phase Equilibria ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Transformation Temperature ◽  
Shape Recovery ◽  
Platinum Group Metals ◽  
Phase Transformation Temperature ◽  
Temperature Phase

The effect of alloying to TiPd and TiPt on phase transformation temperature, phase equilibria, and shape recovery were investigated for TiPt and TiPd base high-temperature shape memory alloys. Ru, Ir, Co and Zr were chosen for additional elements and Zr was found as the most effective element to improve shape recovery of TiPd and TiPt.

Mechanical Properties of (Pt, Ir)Ti

2005 ◽  
Vol 475-479 ◽  
pp. 1987-1990 ◽  
Author(s):  
Yoko Yamabe-Mitarai ◽  
Toru Hara ◽  
Seiji Miura ◽  
Hideki Hosoda
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
High Strength ◽  
Dislocation Motion ◽  
Phase Transformation Temperature ◽  
High Temperature Strength ◽  
Thermal Expansion Measurement ◽  
Cyclic Compression

We have suggested B2-(Pt, Ir)Ti as high temperature shape memory alloys. The phase transformation of (Pt, Ir)-50at% Ti from B2 to B19(2H) or 4H(4O) structures was investigated in our previous study. The microstructure suggested martensitic transformation. In this study, thermal expansion measurement and cyclic compression test were performed for (Pt, Ir)Ti to investigate if the shape memory effect appears. High temperature strength was also investigated because phase transformation temperature of the (Pt, Ir)Ti is above 1273 K and high strength is necessary as high temperature shape memory alloys in order to suppress dislocation motion and stabilize martenstic transformation. The potential of (Pt, Ir)Ti as high temperature shape memory alloys will be also discussed.

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