Structure and properties of severely cold-rolled and annealed Ti–Ni shape memory alloys

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 481; pp. 114 - 118
• Main Authors: Prokoshkin, S.D., Brailovski, V., Inaekyan, K.E., Demers, V., Khmelevskaya, I.Yu, Dobatkin, S.V., Tatyanin, E.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.05.2008
• Subjects: Dislocation substructure; Functional properties; Nanocrystalline structure; Shape memory alloys; Thermomechanical treatment; Titanium nickelide; Functional properties; Nanocrystalline structure; Shape memory alloys; Dislocation substructure; Titanium nickelide; Thermomechanical treatment
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2007.02.150

The substructure and structure formation as well as the mechanical and functional properties of thermomechanically treated Ti–50.7 at.%Ni and Ti–50.0 at.%Ni alloys were studied using transmission electron microscopy and mechanical testing. A low-temperature thermomechanical treatment is carried out by rolling at room temperature in a true strain range e = 0.3–1.9. It is shown that the severe plastic deformation of Ti–Ni alloys results in a partial material amorphization and in the subsequent formation of a nanocrystalline austenite structure during post-deformation annealing. As a result, the completely recoverable strain and recovery stress become much higher than the values reachable using traditional low-temperature thermomechanical treatment with post-deformation annealing which creates a polygonized dislocation substructure.