A5030831134- Shape Memory Alloy Transformations
- Intermetallics and Advanced Alloy Properties
- Magnetic and transport properties of perovskites and related materials
- Heusler alloys: electronic and magnetic properties
- Metallurgical and Alloy Processes
- Magnetic Properties and Applications
- Microstructure and Mechanical Properties of Steels
- High Temperature Alloys and Creep
- Magnetic Properties of Alloys
- Aluminum Alloy Microstructure Properties
- Electronic Packaging and Soldering Technologies
- Titanium Alloys Microstructure and Properties
- Creativity in Education and Neuroscience
- MXene and MAX Phase Materials
- High Entropy Alloys Studies
- Advanced Welding Techniques Analysis
- Solidification and crystal growth phenomena
- Rare-earth and actinide compounds
- Metallurgical Processes and Thermodynamics
- Aluminum Alloys Composites Properties
- Metallurgy and Material Forming
- Microstructure and mechanical properties
- Semiconductor materials and interfaces
- Metallic Glasses and Amorphous Alloys
- nanoparticles nucleation surface interactions
Tohoku University
2016-2025
Institute of Metallurgy
2007-2017
RIKEN Center for Emergent Matter Science
2016
Nippon Soken (Japan)
2016
RIKEN
2016
Lawrence Berkeley National Laboratory
2012
Johannes Gutenberg University Mainz
2012
Tohoku Gakuin University
2009
Japan Science and Technology Agency
2004-2008
Centre for Research in Engineering Surface Technology
2004-2008
Martensitic and magnetic transformations of the Heusler Ni50Mn50−yXy (X=In, Sn Sb) alloys were investigated by differential scanning calorimetry measurement vibrating sample magnetometry technique. In all these alloy systems, austenite phase with ferromagnetic state was transformed into martensite phase, which means that have potential as Ga-free shape memory (FSMAs). Furthermore, multiple martensitic transformations, such two- or three-step occur in systems. It confirmed transmission...
We have identified cobalt-base superalloys showing a high-temperature strength greater than those of conventional nickel-base superalloys. The alloys are strengthened by ternary compound with the L1(2) structure, gamma' Co3(Al,W), which precipitates in disordered gamma face-centered cubic cobalt matrix high coherency and melting points. also compound, Ir3(Al,W), suggests that Co-Ir-Al-W-base systems gamma+gamma' (Co,Ir)3(Al,W) structures offer great promise as candidates for next-generation...
Shape-memory alloys, such as Ni-Ti and Cu-Zn-Al, show a large reversible strain of more than several percent due to superelasticity. In particular, the Ni-Ti-based alloy, which exhibits some ductility excellent superelastic strain, is only material available for practical applications at present. We herein describe ferrous polycrystalline, high-strength, shape-memory alloy exhibiting 13%, with tensile strength above 1 gigapascal, almost twice maximum obtained in alloys. Furthermore, this has...
A superelastic alloy formed from common elements operates over a wide temperature window.
Shape memory and magnetic properties of a Ni43Co7Mn39Sn11 Heusler polycrystalline alloy were investigated by differential scanning calorimetry, the sample extraction method, three-terminal capacitance method. A unique martensitic transformation from ferromagnetic parent phase to antiferromagneticlike martensite was detected magnetic-field-induced “reverse” transition confirmed in high field. In addition, large shape recovery strain about 1.0% observed accompany reverse transformation,...
In polycrystalline materials, grain growth occurs at elevated temperatures to reduce the total area of boundaries with high energy. The rate usually slows down annealing time, making it hard obtain grains larger than a millimeter in size. We report crystal method that employs only cyclic heat treatment single more several centimeters copper-based shape-memory alloy. This abnormal phenomenon results from formation subgrain structure introduced through phase transformation. These findings...
Abstract Producing a single crystal is expensive because of low mass productivity. Therefore, many metallic materials are being used in polycrystalline form, even though material properties superior crystal. Here we show that an extraordinarily large Cu-Al-Mn can be obtained by abnormal grain growth (AGG) induced simple heat treatment with high In AGG, the sub-boundary energy introduced cyclic (CHT) dominant driving pressure, and boundary migration rate accelerated repeating low-temperature...
Abstract In advanced applications such as aerospace and space exploration, materials must balance lightness, functionality extreme thermal fluctuation resistance 1,2 . Shape-memory alloys show promise with strength, toughness substantial strain recovery due to superelasticity, but maintaining low mass effective operation at cryogenic temperatures is challenging 3–6 We hereby introduce a new shape-memory alloy that adheres these stringent criteria. Predominantly composed of Ti Al chemical...
A system of ferromagnetic β phase Ni–Co–Al alloys with an ordered B2 structure that exhibits the shape memory effect has been developed. The this within composition range Ni (30–45 at. %) Co–(27–32 Al, undergo a paramagnetic/ferromagnetic transition as well thermoelastic martensitic transformation from to β′(L10) phase. Curie and start temperatures in can be controlled independently fall 120–420 K. specimens some undergoing β′ are accompanied by effect. These hold great promise new smart materials.
Phase equilibria between the γ and γ′ phases at 900°C in Co-(10–70)Ni-Al-W system were determined by electron probe microanalysis (EPMA) X-ray diffractometry (XRD). It was found that phase with L12 structure continuously exists from Co side to Ni Co-Ni-Al-W it widens low W region increasing content. The partition of Al into increased content, while changed a former increase Differential scanning calorimetry (DSC) measurements also revealed solvus temperature increases solidus is hardly...
The phase equilibria, the martensitic and magnetic transformations in β (B2) region of Co–Ni–Ga Co–Ni–Al systems have been investigated. It is shown that some compositions range Co–(15–30)at%Ni–30 at%Ga Co–(30–40)at%Ni–30 at%Al exhibit both to β′ (L10) thermoelastic transformation para/ferromagnetic transition. Some these undergo from paramagnetic ferromagnetic β′. introduction a small amount γ into by heat treatment, based on results β⁄γ equilibria study systems, significantly improve...
Magnetic and martensitic transition behaviors of a Ni46Mn41In13 Heusler alloy were investigated by differential scanning calorimetry vibrating sample magnetometry. A unique from the ferromagnetic austenite phase to antiferromagneticlike martensite was detected magnetic-field-induced “reverse” confirmed in high magnetic field. In addition, large positive entropy change, which reached 13J∕kgK at 9T, observed accompany reverse transition. This shows promise as metamagnetic shape memory with...
The magnetic and electrical properties on Heusler alloy Ni50Mn36Sn14 were studied in fields up to 18T 4.2–270K temperature range. It was found that at the vicinity of 160K resistivity jump 46% is accompanied by phase transition. Furthermore, large magnetoresistance effect 50% field induced transition observed.
Magnetization and high resolution neutron powder diffraction measurements on the magnetic shape memory compound Ni2Mn1.44Sn0.56 have confirmed that it is ferromagnetic below 319 K undergoes a structural phase transition which takes place at TM = 221 cooling 239 warming. The temperature has cubic L 21 structure, 5.973 Å, with excess manganese atoms occupying 4(b) tin sites. In 245 moments both sites were found to be ferromagnetically aligned. moment 4(a) was 1.88(10) μB but only 0.53(18)...
Magnetic and electrical resistivity changes due to a martensitic transformation in large magnetic fields were investigated NiCoMnIn alloy. The is interrupted at about 150K during field cooling does not proceed with further cooling. obtained two-phase condition frozen low temperatures zero heating releases this condition, inducing “forward” transformation. These unusual phenomena can be explained by an abnormal behavior the entropy change extremely mobility of phase interfaces detected temperatures.