Martensitic transition of traditional NiTi files

Is it totally clear how temperature affect the austenitic or martensitic amount (thus the mechanical properties) of NiTi files at room temperature? Please see the video (real time under microscope) until the end … it could be surprisingly! Heat-treatment is able to change the transitional temperature of NiTi files changing the amount of austenitic and martensitic phase present in the structure of NiTi instruments at room temperature. In general, a traditional NiTi file (NO HEAT-TREATED), like the one in the video, at room temperature (20 degree more or less) is in austenitic phase. Therefore this instrument will be rigid and with shape memory (if you bend the file, it will return back to its original shape - straight); on the…