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Functional behavior of NiTi shape memory alloys is restricted to temperatures below 150 {\deg}C. To shed light on the origin of the loss of functional properties of NiTi with increasing temperature, we have investigated stress induced…

Materials Science · Physics 2024-06-24 O. Tyc , E. Iaparova , O. Molnárová , L. Heller , P. Šittner

Using first-principles based Density Functional Theory (DFT), we have investigated the structural instabilities in the austenite phases of Mn$_{2}$Ni{\it X} ({\it X}= Al, Ga, In, Sn) magnetic shape memory alloys (MSMA). A complete softening…

Materials Science · Physics 2015-06-23 Souvik Paul , Biplab Sanyal , Subhradip Ghosh

We study the branching of twins appearing in shape memory alloys at the interface between austenite and martensite. In the framework of three-dimensional non-linear elasticity theory, we propose an explicit, low-energy construction of the…

Materials Science · Physics 2020-05-20 Hanus Seiner , Paul Plucinsky , Vivekanand Dabade , Barbora Benesova , Richard D. James

Current theoretical studies on structural and magnetic properties of functional Ni-Mn-Z (Z = Ga, In, Sn) Heusler alloys address the origin of the structural transition from the austenite to martensite, and also address the dominant…

Materials Science · Physics 2014-06-04 P Chaddah

Irreversible plastic forming of B19$^\prime$ martensite of the NiTi shape memory alloy is discussed within the framework of continuum mechanics. It is suggested that the main mechanism arises from coupling between martensite reorientation…

Materials Science · Physics 2024-11-01 Hanuš Seiner , Petr Sedlák , Miroslav Frost , Petr Šittner

Additive manufacturing has been vastly applied to fabricate various structures of nickel-titanium (NiTi) shape memory alloys due to its flexibility to create complex structures with minimal defects. However, the microstructure heterogeneity…

Materials Science · Physics 2022-02-22 Shiming Gao , Ojo Philip Bodunde , Mian Qin , Wei-Hsin Liao , Ping Guo

This study explores cardiovascular stents fabricated using laser powder bed fusion (LPBF); an emerging method to offer patient-specific customisable parts. Here, the shape memory alloy NiTi, in a near equiatomic composition, was…

We have synthesized a nominal composition of Ni50Mn30Sn20 alloy using arc melting technique. Rietveld refinement confirms the austenite L21 structure in Fm-3m space group. Electrical resistivity has been found to clearly exhibiting two…

Strongly Correlated Electrons · Physics 2015-11-06 Ramesh Chandra Bhatt , R. S. Meena , H. Kishan , V. P. S. Awana , S. K. Agarwal

In a magnetic shape memory alloy system, we vary composition following phenomenological arguments to tune macroscopic properties. We achieve significantly higher shift in austenite to martensitic phase transition temperature with magnetic…

Strongly Correlated Electrons · Physics 2011-06-09 A. Banerjee , S. Dash , Archana Lakhani , P. Chaddah , X. Chen , R. V. Ramanujan

Martensites are materials that undergo diffusionless, solid-state transitions. The martensitic transition yields properties that depend on the history of the material and may allow it to recover its previous shape after plastic deformation.…

The different contributions to the entropy change linked to the austenite-martensitic transition in a Ni-Mn-Sn metamagnetic shape memory alloy have been determined by combining different experimental techniques. The vibrational contribution…

Shape memory alloys inherit their macroscopic properties from their mesoscale microstructure originated from the martensitic phase transformation. In a cubic to orthorhombic transition, a single variant of marten- site can have a compatible…

Materials Science · Physics 2020-09-23 Oguz Umut Salman , Alphonse Finel , Remi Delville , Dominique Schryvers

This paper reviews the status of molecular dynamics as a method in describing solid-solid phase transitions, and its relationship to continuum approaches. Simulation work done in NiTi and Zr using first principles and semi-empirical…

Materials Science · Physics 2007-05-23 G. J. Ackland

Molecular dynamics simulations are performed to provide a detailed understanding of the functional degradation of shape memory alloys at small scale. The origin of the experimentally reported accumulation of plastic deformation and the…

Materials Science · Physics 2021-04-02 Won-Seok Ko , Won Seok Choi , Guanglong Xu , Pyuck-Pa Cho , Yuji Ikeda , Blazej Grabowski

Changes in stoichiometric NiTi allotropes induced by hydrostatic pressure have been studied employing density functional theory. By modelling the pressure-induced transitions in a way that imitates quasi-static pressure changes, we show…

Materials Science · Physics 2015-03-19 David Holec , Martin Friák , Antonín Dlouhý , Jörg Neugebauer

Martensitic transformations, viewed as continuous transformations between triply periodic minimal surfaces (TPMS), as originally proposed by Hyde and Andersson [Z. Kristallogr. 174, 225 (1986)], is extended to include paths between the…

Materials Science · Physics 2024-02-05 Mengdi Yin , Dimitri D. Vvedensky

The irreversibility of the martensite transition in magnetic shape memory alloys (MSMAs) with respect to external magnetic field is one of the biggest challenges that limits their application as giant caloric materials. This transition is a…

In situ neutron diffraction of the uniaxial tension test was used to study the effect of the surrounding matrix microstructure on the mechanical stability of retained austenite in high-carbon bearing steels. Comparing the samples with…

Materials Science · Physics 2018-07-18 Rohit Voothaluru , Vikram Bedekar , Dunji Yu , Qingge Xie , Ke An , R Scott Hyde

A sharp-interface model describing static equilibrium configurations of shape mory alloys by means of interfacial polyconvex energy density introduced by \v{S}ilhav\'y in 2010 and extended to a quasistatic situation by Kn\"upfer and…

Numerical Analysis · Mathematics 2019-03-26 Miroslav Frost , Martin Kružík , Jan Valdman

Ferromagnetic shape memory alloys Ni$_{2+x}$Mn$_{1-x}$Ga were studied in the range of compositions $0.16 \le x \le 0.36$. Experimental phase diagram, constructed from differential scanning calorimetry, transport and magnetic measurements,…