Modeling of the phase transformation of germanate olivine by using the phase-field method

Abstract

Oilvine, which is the main constituent of the upper mantle on the Earth, undergoes phase transformation to the spinel phase under differential stress due to the high pressure and temperature. Although its phase transformation would be responsible for deep-focus earthquakes, the effect of microstructural properties on the transformation is unclear, such as plastic strain. Therefore, we conducted a phase-field simulation using germanate olivine (Mg₂GeO₄), an analog of silicate olivine. As a result, we revealed that the phase transformation was promoted not by the plastic strain due to the deformation, but by the plastic strain due to the phase transformation.