Positron annihilation studies of microstructural changes in cold-worked Fe–Ni-base aging alloys
✍ Scribed by A.P. Druzhkov; D.A. Perminov
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 632 KB
- Volume
- 527
- Category
- Article
- ISSN
- 0921-5093
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✦ Synopsis
Microstructural evolution of cold-worked fcc Fe-Ni-Ti(Al) aging alloys subjected to isochronal annealing has been investigated using positron annihilation. The stages corresponding to vacancy defect annealing, heterogeneous nucleation of ␥ -phase particles and recrystallization have been clearly identified. It has been found that, due to strong interaction of vacancies with titanium atoms in the Fe-Ni-Ti alloy, lowtemperature (450-700 K) segregation of titanium and formation of Ni 3 Ti particles at dislocations are observed. The Ni 3 Ti particles strongly pin the dislocations, leading to recrystallization retardation. At the same time, particles block positron trapping at dislocations. Decomposition of cold-worked Fe-Ni-Al alloy takes place over the same temperature range (800-900 K) as in the solution annealed state of this alloy. Precipitation of the Ni 3 Al and high-temperature bcc-phase particles also leads to dislocation pinning and inhibiting recovery of the microstructure in cold-worked Fe-Ni-Al alloy.