Dissipation function of the first-order phase transformation inVO2ceramics by internal-friction measurements

Abstract

In order to apply the concept of the dissipation function during the first-order phase transition (FOPT) in solids, we measured the internal friction ${\mathit{Q}}^{\mathrm{-}1}$ and shear modulus μ for a range of frequencies of polycrystalline ceramics ${\mathrm{VO}}_2$ as the sample passed through a FOPT across the temperature range of 300–420 K. The experiment was repeated for different temperature variation rate Ṫ. We have found that for each frequency, a maximum of ${\mathit{Q}}^{\mathrm{-}1}$ and a minimum of μ occurred at the same temperature ${\mathit{T}}_{\mathit{p}}$ when Ṫ was kept constant. The numerical values of the dissipation function Δ${\mathit{G}}_{\mathit{R}}$ plus other FOPT parameters have been deduced using ${\mathit{Q}}^{\mathrm{-}1}$ data. The general trend of Δ${\mathit{G}}_{\mathit{R}\mathrm{-}}$T and other results are found to be consistent with known physical aspects.