Stimulated by recent experimental results on superelastic NiTi shape memory alloy, a theoretical study is carried out to quantify the effect of plasticity on stress-induced martensite transformation, using a constitutive model that combines phase transformation and plasticity. A constraint equation is introduced to quantify the phenomenon of the stabilisation of plasticity on stress-induced mar...

Martensitic transformation associated with a tensile deformation of CuAlMn single crystals in [loo] direction was studied using in-situ transmission electron microscopy. Stress/strain curves obtained during pseudoelastic deformation of microscopic samples were slightly different fiom bulk ones due to martensite formation in the stage of stress increase and a permanent deformation during the fir...

Utilizing electrical resistance measurements in combination with strain observations on single crystals, it was possible to distinguish the austenite to martensite transformation from the detwinning of the martensite behavior during deformation of NiTiCu shape memory alloys. It was found that the electrical resistance change associated with the detwinning of the martensite variants was as high ...

The quantitative characterization of the microstructure evolution in high-Mn steel during deformation is of great importance to understanding its strain-hardening behavior. In the current study, in situ high-energy synchrotron X-ray diffraction was employed to characterize the microstructure evolution in a Fe-17Mn-1.5Al-0.3C steel during a tensile test. The microstructure at different engineeri...

The microstructure of 8 mm diameter wire produced by the severe deformation of 316L austenitic stainless steel has been examined using TEM and X-ray diffraction. The deformation imparted amounts to a true strain of 6.3. Data from previous studies on strain induced transformation of this steel have been combined with new results to show that true strains .2 are required in order to observe mecha...

Many models simulating the behavior of Shape Memory Alloys (SMA) exist nowadays, in the one or three dimensional situation. In most of the cases they are not able to describe the non isothermal behavior of SMA due to the thermomechanical loadings. Indeed, the influence of the stress on the product phase leads to an orientation of the variants, when the temperature creates a self-accomodating ma...

Numerous experimental studies have shown that evolution of the martensite microstructure in shape memory alloys can lead to plastic deformation. This results in poor functional fatigue in many commercial applications, whereby strain incrementally advances with repeated thermal cycling under stress. This can also affect structural fatigue, whereby repeated cycling initiates and grows fatigue cra...

Metastable austenitic steels react to plastic deformation with a thermally and/or mechanically induced martensitic phase transformation. The transformation ?’-martensite can take place directly or indirectly via the intermediate stage of ?-martensite from single-phase austenite. This effect is influenced by stacking fault energy (SFE) steels. An SFE < 20 mJ/m2 known promote indirect conversi...