Rev.Adv.Mater.Sci. (RAMS)
No 1, Vol. 25, 2010, pages 58-66

STRUCTURE AND PROPERTIES OF AGEING AND NONAGEING ALLOYS
Ti49.4Ni50.6 AND Ti50.2Ni49.8 SUBJECTED TO HIGH PRESSURE TORSION

D. Gunderov, N. Kuranova, A. Lukyanov, V. Makarov, E. Prokofiev, A. Pushin

Abstract

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 úC 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 400úC for 1 h a structure with a considerably larger grain size of about 150 nm forms.

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