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.

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.

Effect of Aging on Phase Transition Behavior of Ti50Ni15Pd25Cu10 High Temperature Shape Memory Alloys

2015 ◽  
Vol 1101 ◽  
pp. 177-180 ◽  
Author(s):  
Saif Ur Rehman ◽  
Mushtaq Khan ◽  
Liaqat Ali ◽  
Syed Husain Imran Jaffery
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensite Phase ◽  
Two Stage ◽  
Transformation Temperatures ◽  
Transition Behavior ◽  
Forward Transformation ◽  
Niti Shape Memory Alloys

Formation of Ni4Ti3 precipitates during aging of Ni-rich binary NiTi shape memory alloys and its effect on transition behavior during transformation from austenite to martensite phase has been studied extensively. However for equi-atomic NiTi-based quaternary high temperature shape memory alloy, two-stage martensitic transformation was detected for the first time. The Ti50Ni15Pd25Cu10 high temperature shape memory alloys were investigated for the hardness and transformation temperatures at aging temperature of 550°C. Aging at 550°C for 6 h resulted in remarkable increase in the hardness, whereas the phase transformation temperatures decreased significantly. During forward transformation from austenite to martensite, two-stage martensitic transformation; B2 (cubic) → R-phase and R-phase → B19 (orthorhombic) was observed.

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.

TEM Study of Ni-Mn-Co-In Ferromagnetic Shape Memory Alloys

2012 ◽  
Vol 186 ◽  
pp. 271-274
Author(s):  
Krystian Prusik ◽  
Katarzyna Bałdys ◽  
Danuta Stróż
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Parent Phase ◽  
Cobalt Content ◽  
Indium Content ◽  
Ferromagnetic Shape Memory Alloys ◽  
Transformation Temperatures ◽  
Ferromagnetic Shape Memory

Ferromagnetic shape memory alloys (FSMA) are relatively new smart materials group. Recently, new FSMA from NiMnX (X=Sb, Sn, In, Co+In) systems are considered as alternative to the well known NiMnGa alloys. Four alloys of the following compositions: Ni43Mn35Co4In18, Ni41Mn35Co4In20, Ni42Mn35Co5In18, Ni40Mn35Co5In20 were studied in order to determine microstructure, phase composition and martensitic transformation temperatures versus their chemical composition. Structure of the alloys was studied by optical and transmission electron microscopy (TEM). All of the studied alloys showed macrostructure consisting of radially oriented columnar grains in the direction perpendicular to the casting axis. The structure of the phases occurred in the studied alloys depended on the cobalt and indium content. For the alloys containing 20 at. % of In at room temperature only L21 parent phase was observed whereas for those containing 18 at. % of In either single phase 14M modulated martensite or mixture of 14M martensite and L21 parent phase were seen. DSC measurements showed in studied alloys single-state martensitic transformation. Decrease In content of 2 at.% caused about 80°C fall of martensitic transformation temperatures. Curie temperature Tc increases of 20°C with 1 at% rise of the cobalt content.

scholarly journals Effect of Ni-Content on the Transformation Temperatures in NiTi-20 at. % Zr High Temperature Shape Memory Alloys

Metals ◽  
2017 ◽  
Vol 7 (11) ◽  
pp. 511 ◽  
Author(s):  
Matthew Carl ◽  
Jesse Smith ◽  
Brian Van Doren ◽  
Marcus Young
Keyword(s):  
High Temperature ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Transformation Temperatures ◽  
Ni Content

Transformation Temperatures, Shape Memory and Magnetic Properties of Hafnium Modified Ti-Ta Based High Temperature Shape Memory Alloys

2017 ◽  
Vol 36 (2) ◽  
pp. 113-119
Author(s):  
W.Q. Khan ◽  
Q. Wang ◽  
X. Jin
Keyword(s):  
High Temperature ◽  
Shape Memory ◽  
Alloy System ◽  
Heat Of Reaction ◽  
Transformation Temperatures ◽  
Dsc Measurements ◽  
Recovery Strain ◽  
Shape Memory Properties ◽  
Three Point Bend Test ◽  
Point Bend

AbstractIn this study the modification effect of Hf content on the shape memory properties and magnetic permeability of a 75.5-77Ti-20Ta-3-4.5Hf alloy system has been systematically studied by DSC, three-point bend test, vector network analyzer and XRD. The martensitic transformation temperature, heat of reaction and recovery strain increases with the increase of hafnium and tantalum content. A stable high temperature shape memory effect was observed (Ms = 385–390 °C) during the two thermal cycles between 20 °C and 725 °C. Transformation temperatures and heats of reaction were determined by DSC measurements. Recovery strain was determined by three-point bend testing. Also an alloy, 70Ti-26Ta-4Hf, with higher tantalum content was produced to observe the effect of Ta on the shape memory properties. Permeability increases gradually from 1.671 to 1.919 with increasing content of hafnium modification and remains stable in the frequency range of 450 MHz to 1 GHz.

Martensitic Transformation of High-Entropy and Medium-Entropy Shape Memory Alloys

2021 ◽  
Vol 1016 ◽  
pp. 1802-1810
Author(s):  
Hiromichi Matsuda ◽  
Masayuki Shimojo ◽  
Hideyuki Murakami ◽  
Yoko Yamabe-Mitarai
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Transformation Temperature ◽  
Solid Solution Hardening ◽  
Solution Hardening ◽  
High Entropy ◽  
The One

As new generation of high-temperature shape memory alloys, high-entropy alloys (HEAs) have been attracted for strong solid-solution hardened alloys due to their severe lattice distortion and sluggish diffusion. TiPd is the one potential high-temperature shape memory alloys because of its high martensitic transformation temperature above 500 °C. As constituent elements, Zr expected solid-solution hardening, Pt expected increase of transformation temperature, Au expected keeping transformation temperature, and Co expected not to form harmful phase. By changing the alloy composition slightly, two HEAs and two medium entropy alloys (MEAs) were prepared. Only two MEAs, Ti45Zr5Pd25Pt20Au5, and Ti45Zr5Pd25Pt20Co5 had the martensitic transformation. The perfect recovery was obtained in Ti45Zr5Pd25Pt20Co5 during the repeated thermal cyclic test, training, under 200 MPa. On the other hand, the small irrecoverable strain was remained in Ti45Zr5Pd25Pt20Au5 during the training under 150 MPa because of the small solid-solution hardening effect. It indicates that Ti45Zr5Pd25Pt20Co5 is the one possible HT-SMA working between 342 and 450 °C.

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