High speed scanning calorimetry for amorphous alloys

A high speed scanning calorimeter has been developed for simultaneous measurements of heat capacity and electrical resistivity of thin strips. The system was designed for amorphous alloys but can be used for other materials as well. The specimen is heated by an electrical current at rates ranging from 250 to 40,000 K·s^–1, and the temperature is sensed by an IR pyrometer ranging down to room temperature. The maximum data acquisition rate is 50 kHz. Operational characteristics of the system are given, and various phenomena that affect design and operation are discussed. Data are taken for some Metglas alloys. Glass transition and crystallization temperatures as well as rough viscosity data are evaluated. At high heating rates the glass transition is spread over a wide temperature range. The formation of metastable crystalline phases can be bypassed so that stable phases form directly from the amorphous state.