Multiphase phase-field approach for solid-solid phase transformations via propagating interfacial phase in HMX

In this study, a thermodynamically consistent multiphase phase-field theory has been formulated to describe temperature-induced solid-solid phase transformations via an interfacial phase. This theory satisfies all thermodynamic equilibrium and stability conditions. It allows us to formulate the analytical solutions of the interface profile, energy, width, and velocity for each of the propagating solid-melt and solid-solid interfaces. The formation of the intermediate melt during solid-solid phase transformation has been studied hundreds of degrees below melting temperature in the HMX energetic crystal. The effect of the penalizing term in the phase-field model and two nanoscale material parameters on the appearance and degree of disordering of intermediate melt has been analyzed for the non-equilibrium interface. The developed approach is applicable to phase transitions in geological, pharmaceutical, ferroelectric, colloidal, and superhard materials where phase transformations occur via the intermediate phase.

Automated summary

This study has formulated a thermodynamically consistent multiphase phase-field theory to describe temperature-induced solid-solid phase transformations through an interfacial phase. The theory allows for analytical solutions of interface properties for propagating solid-melt and solid-solid interfaces. The study has focused on the formation of intermediate melt in HMX energetic crystal, analyzing the effect of a penalizing term and nanoscale material parameters on the appearance and degree of disordering of the intermediate phase for non-equilibrium interfaces.