The influence of grain constraint on the magnetic field levels required to complete the isothermal martensitic transformation in magnetic shape memory alloys has been demonstrated for a NiCoMnSn alloy, and the magnetocaloric performance of an optimally heat treated alloy was quantified. Ni45CoxMn45-xSn10 melt spun ribbons with x = 2, 4, 5, and 6 were characterized. The x = 5 sample was determin...

in the present study, the effect of grain size on the austenite stability was studied by nanoindentationtests in a 304l stainless steel. thermomechanical processing based on cold rolling and annealing wasused to produce two different types of austenite: ultrafine grained (ufg) austenite with the averagegrain size of 0.65 μm and coarse grained (cg) austenite with the average grain size of 12 μm....

This paper describes an experimental study of stress-induced martensitic phase transformation in the SMA Nickel-Titanium. The rich local thermo-mechanical interactions that underlie transformation are examined using three-dimensional Digital Image Correlation (strain fields) and infrared imaging (thermal fields). We quantify the complex local interactions between released/absorbed latent heat a...

An open question is the underlying mechanisms for a recent discovered nanocomposite, which composed of shape memory alloy (SMA) matrix with embedded metallic nanowires (NWs), demonstrating novel mechanical properties, such as large quasi-linear elastic strain, low Young's modulus and high yield strength. We use finite element simulations to investigate the interplay between the superelasticity ...

The paper considers the influence of aging of high-temperature phase on subsequent martensitic transformation in Cu-Al-Mn alloy. The morphology of behavior of martensitic transformation as a result of alloy aging under annealing in a constant magnetic field with different sample orientation relatively to the field direction and without field was studied for direct control of the processes of ma...

We have constructed a complete hydrodynamic theory of nucleation and growth in a one–dimensional version of an elastic shear martensitic transformation with open boundary conditions where we have accounted for interfacial energies with strain–gradient contributions. We have studied the critical martensitic nuclei for this problem: Interestingly, the bulk critical nuclei are twinned structures, ...

A phase-field model is developed to study the cubic to monoclinic martensitic phase transformation in nickel–titanium (NiTi) shape memory alloys. Three-dimensional phase-field simulations show the nucleation and growth of monoclinic B190 multivariants that form a polytwinned martensitic microstructure. Parametric studies demonstrate that mechanical constraints and crystallographic orientation g...

In this study the α′′ stress-induced martensitic transformation and damping behaviour of the superelastic β-Ti–25Ta–25Nb alloy are investigated by tensile tests at room temperature and by dynamic mechanical analysis (DMA) in tensile mode for different applied stresses. Tensile tests show a fully non-linear elastic domain and, consequently, a specific method is proposed to determine the elastic ...

This research focuses on the stability of three metastableβ titanium alloys – Ti-10V-1Fe-3Al (T i −1013), Ti-10V-2Cr-3Al (T i −102Cr 3) and Ti-10V-2Fe-3Al-B (T i −1023B). In the first stage of the work, new β+ (α+β) heat treatment schemes were designed on the basis of Thermo-Calc® simulations and previous research work and carried out to such an extent that the β phase stability is tuned to the...

Martensitic transfromation in TiNi alloys of the near-equiatomic composition has been studied by utilizing electron microscopy and diffraction under various thermal treatments. It has been observed that the martensitic transformation is associated with the variants of the product. Two orientations of the martensitic phase were observed as adjacent regions in quenched alloys. These orientations ...