We study the influence of elastic anisotropy on nanoscale precursor textures that exist in some shape-memory alloys and show that tweed occurs in the limit of high elastic anisotropy while a nanocluster phase-separated state occurs for values of anisotropy inhibiting the formation of martensite. These results are consistent with specific heat data, elastic constant measurements, and zero-field ...

Nitinol (Nickel-Titanium) alloys exhibit a combination of properties which make these alloys particularly suited for self-expanding stents. Some of these properties cannot be found in engineering materials used for stents today. The paper describes the fundamental mechanism of shape memory and superelasticity. Material properties and device characteristics like elastic deployment, thermal deplo...

The presented article reviews the first experiences with the xenon plasma focused ion beam (FIB) in the scanning electron microscope (SEM) applied on the investigations of shape memory alloys (SMAs). The SMA are the focus of investigation in our department for many years and these investigated alloys are examples of material prepared by novel spark plasma sintering method (NiTi) and traditional...

*Correspondence: Marcelo J. Dapino, 201 West 19th Avenue, Columbus, OH 43210, USA e-mail: [email protected] Shape memory composites (SMCs) based on shape memory alloys (SMAs) and shape memory polymers (SMPs) allow many design possibilities due to their controllable temperature-dependent mechanical properties. The complementary characteristics of SMAs and SMPs can be utilized in systems with shap...

" Thermomechanical behavior at the nanoscale and size effects in shape memory alloys. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Shape memory alloys (SMA) und...

Tensile and compressive strain–temperature and stress–strain responses have been used for the first time to investigate the effects of second-phase particles on the deformation of NiFeGa shape memory alloys. Particles are conducive to the dissipation of stored energy; stress and thermal hysteresis increase three-fold in aged alloys. Although dissipation is severe, recoverable strain levels are ...

This paper presents a variational multiscale method for developing stabilized finite element formulations for small strain inelasticity. The multiscale method arises from a decomposition of the displacement field into coarse (resolved) and fine (unresolved) scales. The resulting finite element formulation allows arbitrary combinations of interpolation functions for the displacement and pressure...

T his is the fourth paper in our series, identifying unusual phenomena and providing recommendations for the thermo-mechanical characterization of shape memory alloy (SMA) wire. Part 11 provided basic background of the martensitic transformations between austenite (A) and martensite (M) which are responsible for the shape memory (SM) effect and superelasticity (SE). Two typical NiTi SMA alloys ...

In this paper, the mechanical properties and tensile failure mechanism of two novel bio-absorbable as-cast Mg-Zn-Se and Mg-Zn-Cu alloys for endovascular medical applications are characterized. Alloys were manufactured using an ARC melting process and tested as-cast with compositions of Mg-Zn-Se and Mg-Zn-Cu, being 98/1/1 wt.% respectively. Nanoindentation testing conducted at room temperature w...