Mechanical properties and martensitic transformations in nanocrystalline Ti49.4Ni50.6 alloy produced by high-pressure torsion

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 503; no. 1-2; pp. 75 - 77
• Main Authors: GUNDEROV, D, LUKYANOV, A, PROKOFIEV, E, KILMAMETOV, A, PUSHIN, V, VALIEV, R
• Format: Conference Proceeding Journal Article
• Language: Russian; English
• Published: Kidlington Elsevier 15.03.2009
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2008.08.044

Nanocrystalline alloy Ti49.4Ni50.6 (numbers indicate at.%) in the shape of a disc 20 mm in diameter has been successfully produced by high-pressure torsion. High-pressure torsion and annealings at temperatures from 400 to 550 deg C resulted in formation of nanocrystalline structures with the mean grain size (D) in the range 20-300 nm. The alloys with D = 20 nm possess very high ultimate tensile strength (more than 2000 MPa) but limited ductility. The alloys with D = 300 nm possess high ductility and enhanced ultimate tensile strength. There are areas of strain-induced transformation B2-B19' on the tensile curves, but their extent depends on the grain size. The relationship between mechanical behavior and martensitic transformation in nanocrystalline TiNi alloys is considered and discussed.