Non-contact method for the measurement of the enthalpy of fusion applied to binary Zr alloys

A new method for noncontact measurement of the heat of fusion of metallic a lloys has been developed. It was applied to reactive binary Zr alloys in an electromagnetic containerless processing device under reduced gravity cond itions. The method is based on the evaluation of the power balance between induction heating and radiative heat loss during the melting transition. In put power was obtained from measurement of the inductive coupling between t he specimen and the currents in the oscillating circuits of a heating and p ositioning generator. Output power was obtained by evaluation of the total hemispherical emissivity from measurement of the external relaxation time, and of the heat capacity by noncontact ac-calorimetry. The enthalpy and ent ropy of fusion of several binary metallic glass-forming Zr alloys such obta ined exhibit a pronounced correlation with the specific heat capacity at th e liquidus temperature suggesting a reduced ideal glass transition temperat ure almost independent of composition for these alloys.