A shape memory device, and thus the alloy, when not operating is generally held in the martensitic condition. Also the shape memory effect depends on the retransformation of the martensite to the parent phase (i). Use of an alloy in a temperature controlling device, therefore, demands reliability and reproducibility of this retransformation temperature with shape memory cycles and more particul...

The formation of stress-induced martensite in superelastic NiTi was studied by neutron diffraction during uniaxial compressive loading and unloading. The respective phase fractions were determined as a function of the applied stresses using a Rietveld refinement with a March–Dollase texture formulation. Before loading, the specimen was fully austenitic. At the highest applied stress of 2625 MPa...

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...

A significant variant selection is reported in isothermal martensite formed on the surface of an Fe-30% Ni sample. The selection phenomenon is modelled using different descriptions of the martensitic phase transformation. In particular, matrices based on the phenomenological theory of martensite crystallography, the Jaswon and Wheeler distortion, and the continuous face centred cubic-body centr...

In order to discuss the advent of the magnetic-field-induced strains for a single crystal Fe22:0Ni51:5Ga26:5 shape memory alloy, the magnetic easy axis in the 14M martensite phase and the magnetocrystalline anisotropy constant K have been investigated. From the data on the spontaneous thermal expansion and the magnetization curves, the magnetic easy axis of the 14M martensite phase was determin...

The atomic configurations at macrotwin interfaces between microtwinned martensite plates in Ni65Al35 material are investigated using high resolution transmission electron microscopy (HRTEM). The observed structures are interpreted in view of possible formation mechanisms of these interfaces. A distinction is made between cases in which the microtwins, originating from mutually perpendicular {11...

The equimolar CoCrFeMnNi alloy is widely studied for its excellent mechanical properties at cryogenic temperatures. Interestingly, it presents a unique combination of strength and ductility mainly due to the occurrence twinning these low Motivated by desire improve room temperature strength, this study focuses on optimization microstructure through alloying thermomechanical treatments. More spe...

In many cases, due to high surface stress, stress concentration and wear, the metal material starts fail from surface. It is necessary investigate interface evolution characteristics under high-speed collisions for widely used materials. The microstructures strengthening mechanism of Ni balls after with 316 L stainless steel were investigated by a self-designed test system. was found that ultra...