Severe plastic deformation (SPD) of Ni-Ti alloys (Ti-rich and Ni-rich) has been performed by High Pressure Torsion (HPT). Aim of the study was to follow the structural evolution in the samples subjected to SPD, in the martensite ↔ austenite phase transformation temperature region. HPT is carried out at room temperature (RT) on two separate Ni-Ti alloy samples, Ti-rich alloy with martensite finish temperature (Mf) above and Ni-rich with austenite finish temperature (Af) below RT. The samples have been studied by in situ X-ray diffraction (XRD) in order to get information about (i) the transformation characteristics and (ii) the structural evolution after annealing. The results showed that the Ti-rich alloy retained one step phase transformation (Martensite ↔ Austenite) after HPT, as well as HPT followed by heat treatment. In the HPT condition, Ni-rich alloy were found to undergo one step phase transformation (Martensite ↔ Austenite), whereas, heat treatment after HPT resulted in the presence of intermediate R-phase transformation both while heating and cooling in the diffraction chamber.
|Conference||E-MRS Fall Meeting Symposium A InN Material and Alloys|
|Period||1/01/09 → …|