High Temperature Shape Memory Alloys of Ni-Al Base Systems

1991 ◽  
Vol 246 ◽  
Author(s):  
R. Kainuma ◽  
H. Nakano ◽  
K. Oikawa ◽  
K. Ishida ◽  
T. Nishizawa
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Elevated Temperatures ◽  
Al Alloy ◽  
Thermoelastic Martensitic Transformation ◽  
Two Phase ◽  
New Type ◽  
P Matrix ◽  
Fcc Phase

AbstractAn attempt to develop a new type of high temperature shape memory alloys based on the Ni-Al system has been made through microstructural control. Addition of Fe or Mn to the binary Ni-Al alloy results in the formation of a ductile fcc phase in an extremely brittle P matrix phase, leading to an improvement in its ductility. These ductile alloys with β + γ two-phase structure in the Ni-Al-Fe, Ni-Al-Mn and Ni-Al-Mn-Fe systems exhibit a shape memory effect due to a thermoelastic martensitic transformation in the temperature range between -100°C and 700°C; besides, the transformation temperatures are easily controlled by annealing at an appropriate temperature. These alloys are expected to be a new group of shape memory alloys which operate at elevated temperatures.

Development of NiAI(B2)-Base Shape Memory Alloys

1994 ◽  
Vol 360 ◽  
Author(s):  
R. Kainuma ◽  
N. Ono ◽  
K. Ishida
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Elevated Temperatures ◽  
Control Method ◽  
High Yield ◽  
Damping Capacity ◽  
Two Phase ◽  
Cycling Treatment ◽  
New Type ◽  
Characteristic Features

AbstractThe basic concept underlying the alloy design and microstructural control method utilised in developing a new type of β(B2)+ γ (A1) two-phase ductile shape memory alloy in the Ni-Al base systems is briefly reviewed. The characteristic features of the shape memory effect (SME) in the Ni-Al-Fe and Ni-Al-Fe-Mn alloys are reported with particular reference to the transformation and deformation temperatures, the volume fractions of the γ phase, the morphology of the β + γ structure and the effect of cycling. Training by cycling treatment has a significant effect on the degree of shape recovery and pseudo-elasticity in the β + γ two-phase alloys. These duplex β + γ alloys also exhibit a combination of relatively high damping capacity and high yield strength. It is emphasized that these alloys could be expected to fill the need for a new group of shape memory alloys which operate at elevated temperatures over 100°C.

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 On the functional degradation of binary titanium–tantalum high-temperature shape memory alloys — A new concept for fatigue life extension

2014 ◽  
Vol 07 (04) ◽  
pp. 1450042 ◽  
Author(s):  
T. Niendorf ◽  
P. Krooß ◽  
E. Batyrsina ◽  
A. Paulsen ◽  
J. Frenzel ◽  
...  
Keyword(s):  
High Temperature ◽  
Fatigue Life ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Noble Metals ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Life Extension ◽  
Promising Alternative ◽  
Cyclic Degradation

High-temperature shape memory alloys are promising candidates for actuator applications at elevated temperatures. Ternary nickel–titanium-based alloys either contain noble metals which are very expensive, or suffer from poor workability. Titanium–tantalum shape memory alloys represent a promising alternative if one can avoid the cyclic degradation due to the formation of the omega phase. The current study investigates the functional fatigue behavior of Ti – Ta and introduces a new concept providing for pronounced fatigue life extension.

Effects of training on the thermomechanical behavior of NiTiHf and NiTiZr high temperature shape memory alloys

2020 ◽  
Vol 794 ◽  
pp. 139857 ◽  
Author(s):  
O. Karakoc ◽  
K.C. Atli ◽  
A. Evirgen ◽  
J. Pons ◽  
R. Santamarta ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Thermomechanical Behavior
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