Martensite evolution in a NiTi shape memory alloy when thermal cycling under an applied load

Thermal cycling and isothermal deformation response of polycrystalline NiTi: Simulations vs. experiment

“…These observations follow earlier work documenting the formation of planar dislocation arrays during loadbiased thermal cycling of 50.1 and 50.4 at.% Ni-Ti [30]. Plastic deformation has also been proposed to explain progressive widening of the {1 1 0} B2 peak during load-biased thermal cycling [31].…”

Instability of cyclic superelastic deformation of NiTi investigated by synchrotron X-ray diffraction

“…Superelastic deformation of NiTi in tension was already a subject of many dedicated in situ X-ray (neutron) diffraction studies in the literature [17][18][19][20][21][22][23]. Majority of in situ diffraction experiments reported in the literature, however, focused on 1-2 cycles on bulk samples in compression.…”

“…As far as we are aware of, there are no literature reports dealing with in situ X-ray diffraction studies during cyclic superelastic deformation of thin medical grade NiTi wires in tension. There are reports dealing with in situ diffraction studies during 1 or 2 tensile cycles [21], during thermal cycling under tensile load [23] or diffraction studies focusing on structural fatigue of NiTi [8].…”

Evolution of Intergranular Stresses in a Martensitic and an Austenitic NiTi Wire During Loading–Unloading Tensile Deformation

“…The mechanisms of martenite detwinning [4] and stress-induced phase transformation, [5,6] the effect of the microstructures such as phase constitutions, [7,8] grain size, [9,10] precipitates and inclusions, [11][12][13] crystal orientations, [13,14] and deformation conditions [7,8,[14][15][16] on the thermal mechanical behavior and fatigue properties have been studied. New technologies such as in situ EBSD, [17] and in situ neutron and synchrotron X-ray diffractions [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] have recently been used to gain insight into the material behavior at the microscopic level. The evolution of martensite texture during thermal cycling and deformation, [18][19][20] the elastic modulus of the monoclinic martensite, [20][21][22][23][24] the phase transformation and strain partitioning during the stress-induced martensite (SIM) phase transformation, [25] and the micro-mechanical behavior at the crack tip of martenstic …”

“…New technologies such as in situ EBSD, [17] and in situ neutron and synchrotron X-ray diffractions [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] have recently been used to gain insight into the material behavior at the microscopic level. The evolution of martensite texture during thermal cycling and deformation, [18][19][20] the elastic modulus of the monoclinic martensite, [20][21][22][23][24] the phase transformation and strain partitioning during the stress-induced martensite (SIM) phase transformation, [25] and the micro-mechanical behavior at the crack tip of martenstic [32] and austenitic [33] NiTi alloys have been analyzed by in situ techniques. These studies improved our fundamental knowledge of the micromechanics of NiTi alloys.…”