Martensite stabilization and thermal cycling stability of two-phase NiMnGa-based high-temperature shape memory alloys

2012 ◽  
Vol 60 (10) ◽  
pp. 4255-4267 ◽  
Author(s):  
Shuiyuan Yang ◽  
Yong Liu ◽  
Cuiping Wang ◽  
Xingjun Liu
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Cycling Stability ◽  
Two Phase ◽  
Martensite Stabilization

scholarly journals Characterization of Ternary NiTiPd High-Temperature Shape-Memory Alloys under Load-Biased Thermal Cycling

2010 ◽  
Vol 41 (12) ◽  
pp. 3065-3079 ◽  
Author(s):  
Glen S. Bigelow ◽  
Santo A. Padula ◽  
Anita Garg ◽  
Darrell Gaydosh ◽  
Ronald D. Noebe
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
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).

Modeling of Cyclic Response of High Temperature Shape Memory Alloys Undergoing Viscoplastic Mechanisms

2010 ◽  
Author(s):  
George Chatzigeorgiou ◽  
Yves Chemisky ◽  
Dimitris C. Lagoudas
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Heating Rate ◽  
Evolution Equations ◽  
Experimental Tests ◽  
Energy Potential ◽  
Slow Cooling ◽  
Cyclic Response

In this work we present a constitutive model for High Temperature Shape Memory Alloys (HTSMAs), where the appearence of viscoplastic mechanisms during transformation influences the cyclic response of the actuator performance. Based on previous models developed for conventional SMAs, a Gibbs free energy potential is defined and the evolution equations for forward, reverse transformation, plasticity occuring during transformation, retained martensite and viscoplasticity are properly chosen. The calibration of the model is achieved with the help of experimental tests performed on TiPdNi alloy. The transformation behavior of the material is calibrated using fast load biased thermal cycling tests at selected stress levels with fast cooling/heating rate. The viscoplastic behavior of the HTSMA is captured with creep and uniaxial tests at appropriate temperature levels. Predictions of the model are compared with load biased thermal cycling tests at slow cooling/heating rate, where viscoplastic strains are significant.

scholarly journals Effect of Stoichiometry on Shape Memory Properties and Functional Stability of Ti–Ni–Pd Alloys

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 798 ◽  
Author(s):  
Yuki Hattori ◽  
Takahiro Taguchi ◽  
Hee Kim ◽  
Shuichi Miyazaki
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Stoichiometric Composition ◽  
Atomic Ratio ◽  
Transformation Temperatures ◽  
Shape Memory Properties ◽  
Ti Content

Ti–Ni–Pd shape memory alloys are promising candidates for high-temperature actuators operating at above 373 K. One of the key issues in developing high-temperature shape memory alloys is the degradation of shape memory properties and dimensional stabilities because plastic deformation becomes more pronounced at higher working temperature ranges. In this study, the effect of the Ti:(Ni + Pd) atomic ratio in TixNi70−xPd30 alloys with Ti content in the range from 49 at.% to 52 at.% on the martensitic transformation temperatures, microstructures and shape memory properties during thermal cycling under constant stresses were investigated. The martensitic transformation temperatures decreased with increasing or decreasing Ti content from the stoichiometric composition. In both Ti-rich and Ti-lean alloys, the transformation temperatures decreased during thermal cycling and the degree of decrease in the transformation temperatures became more pronounced as the composition of the alloy departed from the stoichiometric composition. Ti2Pd and P phases were formed during thermal cycling in Ti-rich and Ti-lean alloys, respectively. Both Ti-rich and Ti-lean alloys exhibited superior dimensional stabilities and excellent shape memory properties with higher recovery ratio and larger work output during thermal cycling under constant stresses when compared with the alloys with near-stoichiometric composition.

scholarly journals Martensitic Transformation and Its Thermal Cycling Stability in Ni56Mn21Cu4Ga19 High-Temperature Shape Memory Ribbon

2014 ◽  
Vol 28 (2) ◽  
pp. 243-248 ◽  
Author(s):  
Xi-Li Lu ◽  
De-Xi Su ◽  
Feng Chen ◽  
Wei-Li Liu ◽  
Yang-Guang Shi ◽  
...  
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Cycling Stability

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.

Thermal cycling effects in high temperature Cu–Al–Ni–Mn–B shape memory alloys

1997 ◽  
Vol 12 (9) ◽  
pp. 2288-2297 ◽  
Author(s):  
J. Font ◽  
J. Muntasell ◽  
J. Pons ◽  
E. Cesari
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Parent Phase ◽  
Aluminum Boride ◽  
Transformation Temperatures ◽  
Dsc Measurements ◽  
Number Of Cycles

The effects of thermal cycling through the martensitic transformation have been studied in three Cu–Al–Ni–Mn–B high temperature shape memory alloys. An increase of the martensitic transformation temperatures with the number of cycles (up to ∼7 K after 60 cycles) has been generally observed by DSC measurements. The microstructure of these alloys is rather complicated, with the presence of big manganese or aluminum boride particles and small boron precipitates, as well as the formation of dislocations during thermal cycling. By means of aging experiments, it has been shown that the evolution of transformation temperatures during cycling is mainly due to the step-by-step aging in parent phase accompanying the thermal cycling, and that the dislocations formed during cycling have only a very small effect, at least up to 60 cycles.

Influence of Cu addition on transformation temperatures and thermal stability of TiNiPd high temperature shape memory alloys

2017 ◽  
Vol 233 (5) ◽  
pp. 800-808
Author(s):  
Saif ur Rehman ◽  
Mushtaq Khan ◽  
A Nusair Khan ◽  
Khurshid Alam ◽  
Syed Husain Imran Jaffery ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Shape Memory Alloys ◽  
Thermal Cycling ◽  
Shape Memory ◽  
Thermal Hysteresis ◽  
Transformation Temperatures ◽  
Cu Content ◽  
Positive Effect ◽  
Thermal Stability Of

In this research, four high temperature shape memory alloys, Ti50Ni25-xPd25Cux (x = 0, 5, 10 and 15) were developed and designated 0Cu, 5 Cu, 10 Cu, and 15Cu, respectively. The effect of 5%, 10%, and 15% (all in atomic percent) Cu addition was investigated through their microstructure analysis, transformation temperatures and thermal stability. After the alloying of Cu content in their desired percentage, the alloys were named as 0Cu, 5Cu, 10Cu and 15Cu alloys. The martensite onset temperature Ms of ternary 0Cu alloy increased by 12.5 ℃, 27.5 ℃ and 60.5 ℃, respectively, by replacement of Ni with 5%, 10% and 15% Cu. Similarly, the austenite finish temperature Af increased by 11 ℃, 25 ℃, and 52 ℃, respectively. At the same time, thermal hysteresis of the 5Cu, 10Cu, and 15Cu alloys decreased by 1.5 ℃, 2.5 ℃, and 8.5 ℃, respectively, as compared to 0Cu alloy. The thermal stability of ternary 0Cu alloy was improved by replacing Ni with Cu. During thermal cycling, the net drop in Ms and Af of 0Cu alloy was 7.5 ℃ and 14 ℃, respectively. By replacing Ni with 5%, 10%, and 15% Cu, the net drop in Ms decreased to 5 ℃, 3.7 ℃, and 3 ℃, respectively, whereas the net drop in Af decreased to 10 ℃, 8.7 ℃, and 5 ℃. The overall results suggested that by the addition of 5%, 10%, and 15% Cu in place of Ni in TiNiPd alloys, the transformation temperatures and thermal stability improved. At the same time, thermal hysteresis decreased to a reasonable level which has a positive effect on the actuation behavior.

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