Особенности развития термоупругих мартенситных превращений под нагрузкой в [110]-монокристаллах сплава Ni[51]Fe[18]Ga[27]Co[4]

Abstract

In the present study, we investigated the stress-indused termoelastic martensitic transformations in Ni[51]Fe[18]Ga[27]Co[4] single crystals oriented along the [110]-direction. It was shown that high-temperature annealing at a temperature higher than the order-disorder transition temperature affects of the stress-indused termoelastic martensitic transformations due to a change in the structure of the high-temperature phase of L21 by B2, the dissolution of the [gamma] − phase. The isobaric experiments (shape memory effect) under external applied stress [sigma]=100 МПа have shown that for (L21+[gamma]) -crystals of the reversible deformation is [epsilon] SME = 2,1 % with insignificant irreversibility and thermal hysteresi s [delta] Т=(29 ± 2) K. For В2-crystals the reversible deformation [epsilon] SME = 4,5%, accompanied by the presence of an irreversible deformation to 1,6% and the thermal hysteresis value [delta] T=(61 ± 2) K. The isothermal experiments (superelasticity) shown the energy dissipation at T=323 K is [sigma]=(89 ± 2) MPa and decreases with increasing test temperature in the B2-crystals.