Thermally induced reorientation and plastic deformation of B19’ monoclinic martensite in nanocrystalline NiTi wires

Electric resistivity evolution in NiTi alloys under thermomechanical loading: phase proportioning, elasticity and plasticity effects

“…First, a PP loading was performed (figures [10][11][12][13]. By observing only the stress vs. strain response, the behavior seems to agree with the standard SMA-response based on literature experimental curves [1,2,28] Typically, the end of SP (strain plateau) is associated with the end of phase transformation or reorientation.…”

“…First, during the effective phase transformation, dislocation slips are probably triggered by transformation-induced plasticity (TRIP) mechanisms [8,31,45,46], which is linked to the change in the slope of the z M σ evolution. Second, when the phase transformation is finished, the twinninginduced plasticity (TWIP) becomes the major actor, which is responsible for the abrupt change of z M σ /ε tr relation and for the z M σ value beyond 1 [10,11,47]. Furthermore, the resistivity curve shows again an incompatible evolution with the presented loading in figure 21, increasing over the maximum possible value of (resistivity for the full stress-induced martensite).…”

“…In the second case, plastic effects are more intense and complex. In some works [8,9,10,11], the authors investigated this phenomenon and analyzed the evolution of different parameters during high stress experiments. It was highlighted that for temperatures much higher than A f , dislocation slip can occur during transformation, resulting in a considerable amount of unrecoverable deformation and changing considerably the kinetics of MT (martensitic transformation) or DT (detwinning).…”