| Nanocrystalline (NC) samples of ageing and nonageing Ti49.4Ni50.6 and Ti50.2Ni49.8 alloys have been produced using high pressure torsion (HPT) by the technique that allows obtaining disc-shaped samples of 20 mm in diameter and 0.7 mm thick. It was revealed that in these Ti-Ni alloys a structure of a mix of amorphous phase and nanocrystalline B2 phase forms after HPT. Microstructure and mechanical properties of the Ti-Ni alloy after HPT and annealing with different temperatures and time (from 5 minutes to 6 days) were investigated. It was revealed that in Ti49.4Ni50.6 alloy after HPT and annealing at 400-500 œC for 1 h a nanostructure forms with the grain size of 30 and 50 nm respectively. In Ti50.2Ni49.8 alloy after HPT and annealing at 400œC for 1 h a structure with a considerably larger grain size of about 150 nm forms. |
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