2. Transformation point analysis

Any physicochemical phase change in alloys, whether it be the α → γ transformation in steels or the formation and dissolution of precipitates, is accompanied by a change in physical or mechanical properties. Thermal, dilatometric, magnetic, and electrical resistivity analysis methods are among the most convenient for measuring these variations [P 1 205] . Optical analysis, using special devices (heating plates), makes it possible to monitor the kinetics of these transformations.