Peculiarities of residual strain accumulation during thermal cycling of TiNi alloy

Investigation of TiNi shape memory alloy for thermosensitive wire drive

“…All functional properties of a TiNi alloy depend on the number of thermal-deformation cycles [14][15][16][17][18][19][20][21]. To determine this dependence for the given alloy, thermocycling of the wire samples under different stresses was conducted.…”

Microstructure transformation and physical and mechanical properties of ultrafine‐grained and nanocrystalline TiNi alloys in multiple martensitic transformations B2‐B19’

“…"Thermocycle training" of TiNi alloys to enhance the memory effect is described in [17][18][19]. In TiNi the shape memory effect and transformation ductility enhance, and the "training" effect is possible, if residual strain accumulates in material [17].…”

“…"Thermocycle training" of TiNi alloys to enhance the memory effect is described in [17][18][19]. In TiNi the shape memory effect and transformation ductility enhance, and the "training" effect is possible, if residual strain accumulates in material [17]. Accommodation of martensite variants occurs elastically in 50 % of the temperature range of the full direct transformation, and plastic accommodation takes place only at the last quarter of the temperature range.…”

“…Thus, the impact of ultrafinegrained structure of TiNi alloys on the phase hardening processes is an issue that requires special studies. A lot number of works (in this paper the term "coarse-grained" is used towards alloys with a grain size of over 1 mm and not relating to ultrafinegrained or nanocrystalline alloys) is dedicated to the thermal cycling impact on the structure and properties of coarse-grained (CG) TiNi alloys [10,[17][18][19]. The studies of thermal cycling impact on ultrafinegrained and nanocrystalline alloys were performed in the restricted volume and mainly dealt with the change of martensitic transformation temperatures and shape memory effect during thermal cycling, whereas the evolution of mechanical properties and structure were not practically studied [19][20][21][22][23][24].…”

Microstructural and Mechanical Stability of a Ti-50.8 at.% Ni Shape Memory Alloy Achieved by Thermal Cycling with a Large Number of Cycles

“…At the same time, other studies report slightly different dependences of the transformation temperatures upon thermal cycling under an applied load [20,21]. There are additional studies of the "thermocyclic training" of TiNi alloys to enhance memory effects [20,[22][23][24]. However, the studies were carried out mainly on alloys in a coarse-grained (CG) state, or in states with a small degree of deformation, and there is a limited number of studies on the processes of accumulation of dislocations and change in properties during thermal cycling of TiNi alloys in UFG and nanocrystalline (NC) states [25].…”