5 Werkstofftechnik
Filtern
Erscheinungsjahr
- 2021 (1) (entfernen)
Dokumenttyp
- Zeitschriftenartikel (1) (entfernen)
Sprache
- Englisch (1)
Referierte Publikation
- ja (1)
Schlagworte
- Thermal Cycling (1) (entfernen)
Organisationseinheit der BAM
- 5 Werkstofftechnik (1) (entfernen)
Thermal cycling of a Ni-excess NiTi alloy was conducted between 50 °C and liquid nitrogen temperature to induce martensitic transformations and to reverse them after. The starting point was an annealed and slowly cooled state, the end point a sample thermally cycled 1500 times. Positron annihilation lifetime spectra and Coincidence Doppler Broadening profiles were obtained in various states and at various tem- peratures. It was found that the initial state was low in defects with positron lifetimes close to that of bulk NiTi. Cycling lead to a continuous build-up of a defect structure up to 20 0 −50 0 cycles after which saturation was reached. Two types of defects created during cycling were identified, namely pure dislo- cations and vacancies attached to dislocations.