Shape Memory Alloys 2014

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (28 February 2015) | Viewed by 31247

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Department of Physics, Cavendish Laboratory, University of Cambridge, CB3, 0HE, UK
Interests: neutron scattering; low temperature physics; strongly correlated systems; magnetism; functional materials; spintronics; novel materials
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Dear Colleagues,

More than half a century has elapsed since research on Au-Cd alloys stimulated world-wide interest in shape memory and super-elastic behavior. Both the microscopic and mesoscopic transformation processes associated with the essential martensitic phase transition have been extensively studied in a wide range of materials. Consequently, these materials are finding use as sensors, actuators, etc., in fields as diverse as medicine and aviation. Although the phase transition is usually thermally or mechanically driven, more recent research has focused on the ability to achieve this using magnetic fields in ferromagnetic alloys. However, many of the materials studied are brittle which would appear to limit their application. This constraint may be overcome by incorporating the materials in hybrid composites. The possibility of doing this, or incorporating shape memory alloys with other smart materials, opens up new areas of fundamental and applied research.

Prof. Dr. Kurt R Ziebeck
Guest Editor

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Keywords

  • shape memory
  • phase transitions
  • magnetism
  • transport properties
  • neutron
  • xray and electron scattering
  • smart materials

Published Papers (5 papers)

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Research

1098 KiB  
Article
Effect of Cu Content on Atomic Positions of Ti50Ni50xCux Shape Memory Alloys Based on Density Functional Theory Calculations
by Liangliang Gou, Yong Liu and Teng Yong Ng
Metals 2015, 5(4), 2222-2235; https://doi.org/10.3390/met5042222 - 26 Nov 2015
Cited by 7 | Viewed by 6671
Abstract
The study of crystal structures in shape memory alloys is of fundamental importance for understanding the shape memory effect. In order to investigate the mechanism of how Cu content affects martensite crystal structures of TiNiCu alloys, the present research examines the atomic displacement [...] Read more.
The study of crystal structures in shape memory alloys is of fundamental importance for understanding the shape memory effect. In order to investigate the mechanism of how Cu content affects martensite crystal structures of TiNiCu alloys, the present research examines the atomic displacement of Ti50Ni50xCux (x = 0, 5, 12.5, 15, 18.75, 20, 25) shape memory alloys using density functional theory (DFT). By the introduction of Cu atoms into TiNi martensite crystal to replace Ni, the displacements of Ti and Ni/Cu atoms along the x-axis are obvious, but they are minimal along the y- and z-axes. It is found that along the x-axis, the two Ti atoms in the unit cell move in opposite directions, and the same occurred with the two Ni/Cu atoms. With increasing Cu content, the distance between the two Ni/Cu atoms increases while the Ti atoms draw closer along the x-axis, leading to a rotation of the (100) plane, which is responsible for the decrease in the monoclinic angle. It is also found that the displacements of both Ti atoms and Ni/Cu atoms along the x-axis are progressive, which results in a gradual change of monoclinic angle and a transition to B19 martensite crystal structure. Full article
(This article belongs to the Special Issue Shape Memory Alloys 2014)
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703 KiB  
Article
Structure and Mössbauer Analysis of Melt-Spun Fe-Pd Ribbons Containing Ni and Co
by Hanen Rekik, Mahmoud Chemingui, Tarek Bachaga, Amal Cherif, Pere Bruna, Joan Joseph Sunol and Mohamed Khitouni
Metals 2015, 5(2), 1020-1028; https://doi.org/10.3390/met5021020 - 05 Jun 2015
Cited by 5 | Viewed by 5237
Abstract
Fe68.45Pd28.21Co1.66Ni1.66 alloy in ribbon geometry was produced by melt spinning. The microstructure of the samples was examined using scanning electron microscopy. The structural identification of the as-spun ribbon sample and the annealed ones was performed by [...] Read more.
Fe68.45Pd28.21Co1.66Ni1.66 alloy in ribbon geometry was produced by melt spinning. The microstructure of the samples was examined using scanning electron microscopy. The structural identification of the as-spun ribbon sample and the annealed ones was performed by means of X-ray diffraction. All the Bragg peaks were indexed based on an fcc type structure of (γ-Fe, Pd) phase with a lattice parameter a = 3.742 (3) Å. This result was proved by Mössbauer technique. The annealed ribbon at 600 °C shows an L10 ordered fct structure. An endothermic reaction at T = 358 °C followed by an exothermic one at 390 °C were observed on heating. These reactions were attributed to the Curie temperature of nickel and to the annihilation of an excess of quenched-in vacancies, respectively. Full article
(This article belongs to the Special Issue Shape Memory Alloys 2014)
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1964 KiB  
Article
Martensitic Transformation in Ni-Mn-Sn-Co Heusler Alloys
by Alexandre Deltell, Lluisa Escoda, Joan Saurina and Joan Josep Suñol
Metals 2015, 5(2), 695-705; https://doi.org/10.3390/met5020695 - 28 Apr 2015
Cited by 16 | Viewed by 5921
Abstract
Thermal and structural austenite to martensite reversible transition was studied in melt spun ribbons of Ni50Mn40Sn5Co5, Ni50Mn37.5Sn7.5Co5 and Ni50Mn35Sn10Co5 (at. %) [...] Read more.
Thermal and structural austenite to martensite reversible transition was studied in melt spun ribbons of Ni50Mn40Sn5Co5, Ni50Mn37.5Sn7.5Co5 and Ni50Mn35Sn10Co5 (at. %) alloys. Analysis of X-ray diffraction patterns confirms that all alloys have martensitic structure at room temperature: four layered orthorhombic 4O for Ni50Mn40Sn5Co5, four layered orthorhombic 4O and seven-layered monoclinic 14M for Ni50Mn37.5Sn7.5Co5 and seven-layered monoclinic 14M for Ni50Mn35Sn5Co5. Analysis of differential scanning calorimetry scans shows that higher enthalpy and entropy changes are obtained for alloy Ni50Mn37.5Sn7.5Co5, whereas transition temperatures increases as increasing valence electron density. Full article
(This article belongs to the Special Issue Shape Memory Alloys 2014)
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2528 KiB  
Article
Effects of Annealing on the Martensitic Transformation of Ni-Based Ferromagnetic Shape Memory Heusler Alloys and Nanoparticles
by Tina Fichtner, Changhai Wang, Aleksandr A. Levin, Guido Kreiner, Catalina Salazar Mejia, Simone Fabbrici, Franca Albertini and Claudia Felser
Metals 2015, 5(2), 484-503; https://doi.org/10.3390/met5020484 - 25 Mar 2015
Cited by 14 | Viewed by 6416
Abstract
We report on the effects of annealing on the martensitic phase transformation in the Ni-based Heusler system: Mn50Ni40Sn10 and Mn50Ni41Sn9 powder and Co50Ni21Ga32 nanoparticles. For the powdered Mn50Ni40Sn10 and Mn50Ni41Sn9 alloys, structural and magnetic measurements reveal that post-annealing decreases the martensitic transformation temperatures [...] Read more.
We report on the effects of annealing on the martensitic phase transformation in the Ni-based Heusler system: Mn50Ni40Sn10 and Mn50Ni41Sn9 powder and Co50Ni21Ga32 nanoparticles. For the powdered Mn50Ni40Sn10 and Mn50Ni41Sn9 alloys, structural and magnetic measurements reveal that post-annealing decreases the martensitic transformation temperatures and increases the transition hysteresis. This might be associated with a release of stress in the Mn50Ni40Sn10 and Mn50Ni41Sn9 alloys during the annealing process. However, in the case of Co50Ni21Ga32 nanoparticles, a reverse phenomenon is observed. X-ray diffraction analysis results reveal that the as-prepared Co50Ni21Ga32 nanoparticles do not show a martensitic phase at room temperature. Post-annealing followed by ice quenching, however, is found to trigger the formation of the martensitic phase. The presence of the martensitic transition is attributed to annealing-induced particle growth and the stress introduced during quenching. Full article
(This article belongs to the Special Issue Shape Memory Alloys 2014)
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1107 KiB  
Article
Magnetic Field-Induced Reverse Martensitic Transformation and Thermal Transformation Arrest Phenomenon of Ni41Co9Mn39Sb11 Alloy
by Rie Y. Umetsu, Xiao Xu, Wataru Ito, Takumi Kihara, Kohki Takahashi, Masashi Tokunaga and Ryosuke Kainuma
Metals 2014, 4(4), 609-622; https://doi.org/10.3390/met4040609 - 18 Dec 2014
Cited by 13 | Viewed by 6470
Abstract
In order to investigate behavior of magnetic field-induced reverse martensitic transformation for Ni-Co-Mn-Sb, magnetization experiments up to a static magnetic field of 18 T and a pulsed magnetic field of 40 T were carried out. In the thermomagnetization curves for Ni41Co [...] Read more.
In order to investigate behavior of magnetic field-induced reverse martensitic transformation for Ni-Co-Mn-Sb, magnetization experiments up to a static magnetic field of 18 T and a pulsed magnetic field of 40 T were carried out. In the thermomagnetization curves for Ni41Co9Mn39Sb11 alloy, the equilibrium transformation temperature T0 was observed to decrease with increasing applied magnetic field, μ0H, at a rate of dT0/dμ0H = 4.6 K/T. The estimated value of entropy change evaluated from the Clausius-Clapeyron relation was about 14.1 J/(K·kg), which was in good agreement with the value obtained by differential scanning calorimetric measurements. For the isothermal magnetization curves, metamagnetic behavior associated with the magnetic field-induced martensitic transformation was observed. The equilibrium magnetic field, μ0H0 = (μ0HAf + μ0HMs)/2, of the martensitic transformation tended to be saturated at lower temperature; that is, transformation arrest phenomenon was confirmed for the Ni-Co-Mn-Sb system, analogous with the Ni(Co)-Mn-Z (Z = In, Sn, Ga, Al) alloys. Temperature dependence of the magnetic field hysteresis, μ0Hhys = μ0HAf − μ0HMs, was analyzed based on the model for the plastic deformation introduced by the dislocations. The behavior can be explained by the model and the difference of the sweeping rate of the applied magnetic field was well reflected by the experimental results. Full article
(This article belongs to the Special Issue Shape Memory Alloys 2014)
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