A study on the mechanical behavior and microstructural evolution of Ni60Â wt%-Ti40Â wt% (60Nitinol) intermetallic compound during hot deformation

The results show that there was a delay in the occurrence of DRX as the deformation temperature increased from 950 to 1050 °C. The results also indicate that the activation energy and the strain rate sensitivity of Ni60 wt%-Ti40 wt% alloy vary abnormally with strain. The possible mechanisms dominated during the hot deformation of this alloy were determined and discussed. These results imply that there is a temperature and strain rate range when the workability of this alloy is significantly reduced. For example, there are some abnormalities in the flow curve when the deformation temperature drops below 950 °C. The lack of sufficient workability of 60Nitinol can be attributed to the high volume fraction of intermetallic compounds. It can be concluded that dynamic recrystallization can be considered as the dominate restoration mechanism. With increasing the strain from 0.2 to 1, the dynamically recrystallized grains become more prevalent. At the strain of 1.0, the DRX phenomenon has extended significantly so that there is almost no sign of the initial grains. Finally, a theoretical model was developed for the hot-deformation behavior of this alloy.