What are the exact temperatures at which austenite-marsentite phase transition takes place for NITINOL alloy?

Actually, the composition and heat treatment of Nitinol can be changed to influence the transformation temperature. There are now a good number of shape memory alloys used in medical applications. For these applications, the transformation temperature is below body temperature (98.6�F) so that the phase change happens as soon as the device is placed in the body.