Alloy
Af Temperature (Austenite Finish)
Definition
The temperature at which a NiTi alloy completes its transformation to the austenitic phase on warming. Files with an Af above body temperature remain partly martensitic in the canal — generally more flexible, more resistant to cyclic fatigue, and in some alloys pre-bendable — while files with an Af below body temperature behave superelastically. Reported values depend on the manufacturer and measurement method, so Af is a design signal rather than a standalone predictor of clinical performance.