DISSIPATION FUNCTION OF THE FIRST-ORDER PHASE-TRANSFORMATION IN VO2 CERAMICS BY INTERNAL-FRICTION MEASUREMENTS

In order to apply the concept of the dissipation function during the first-order phase transition (FOPT) in solids, we measured the internal friction Q-1 and shear modulus for a range of frequencies of polycrystalline ceramics VO2 as the sample passed through a FOPT across the temperature range of 300 420 K. The experiment was repeated for different temperature variation rate T. We have found that for each frequency, a maximum of Q-1 and a minimum of occurred at the same temperature Tp when T was kept constant. The numerical values of the dissipation function GR plus other FOPT parameters have been deduced using Q-1 data. The general trend of GR-T and other results are found to be consistent with known physical aspects. © 1995 The American Physical Society.