Magnetic shape memory properties of Ni-Mn-Ga single crystals were characterized by measurement of stress-induced martensite reorientation under constant magnetic fields. Also magnetic field-induced strain as a function of the applied magnetic field under different constant compressive stress levels has been investigated. All the experiments were performed at room temperature in which the sample...

Shape memory alloys exhibit a high damping capacity in the mktensite state. Results obtained from both DMA and cyclic tests under tension-compression load show that the martensite damping capacity in NiTi SMAs is a function of both strain amplitude and annealing temperature. Internal friction due to movements of martensite twin boundaries within both elastic (accommodation) and inelastic (reori...

Pseudoelasticity and the shape memory e ect (SME) due to martensitic transformation and reorientation of polycrystalline shape memory alloy (SMA) materials are modelled using a free energy function and a dissipation potential. Three di erent cases are considered, based on the number of internal state variables in the free energy: (1) Austenite plus a variable number of martensite variants; (2) ...

NiTi wires were brazed together via eutectic reaction between NiTi and Nb powder deposited at the wire contact region. Phase transformation and deformation behavior of the NiTi-Nb eutectic microstructure were investigated using transmission electron microscopy (TEM) and cyclic loading-unloading tests. Results show that R phase and B19' martensite transformation are induced by plastic deformatio...

The present paper aims at providing a fine-scale analysis of the Ti-4.5Al-2.5Fe-0.25Si α+α’+βretained microstructures to give insight into link between microstructural characteristics alloy (phase fraction and chemistry, grain size, etc.) deformation mechanisms play. These were found exhibit outstanding work-hardening capabilities that have great potential be obtained simultaneously with high y...

the pseudo-elastic behavior of shape memory alloy (sma) truss and cantilever beam are investigated. brinson’s one-dimensional material model, which uses the twinned and detwinned martensite fractions separately as internal variables, is applied in the algorithm to establish the sma stress-strain characteristics. this material model also incorporates different young’s modulus for austenitic and ...

Abstract Deformation mechanisms activated during tensile deformation of nanocrystalline NiTi wire in martensite state were investigated by combination two experimental methods: (i) analysis the evolution martensite-variant microstructures grains deformed TEM and (ii) texture situ synchrotron X-ray diffraction. The obtained results are linked to activity various twinning processes martensite. It...

Large magnetic-field-induced strain ~MFIS! of 22700 ppm has been obtained from the Heusler alloy Ni52Mn23Ga25 at 300 K. The temperature for structure transformation was confirmed by three types of magnetic measurements. A burst of MFIS up to 5400 ppm could be induced by rotating a steady field of 1 T. In the martensitic phase, the material have a high saturated magnetization of 66 Am/kg and a h...