At high temperature and pressure, solid diffusion and chemical reactions between rock minerals lead to phase transformations. Chemical transport during uphill diffusion causes phase separation, that is, spinodal decomposition. Thus, to describe the coarsening kinetics of the exsolution microstructure, we derive a thermodynamically consistent continuum theory for the multicomponent Cahn–Hilliard equations while accounting for multiple chemical reactions and neglecting deformations. Our approach considers multiple balances of microforces augmented by multiple component content balance equations within an extended Larché–Cahn framework. As for the Larché–Cahn framework, we incorporate into the theory the Larché–Cahn derivatives with respect to the phase fields and their gradients. We also explain the implications of the resulting constrained gradients of the phase fields in the form of the gradient energy coefficients. Moreover, we derive a configurational balance that includes all the associated configurational fields in agreement with the Larché–Cahn framework. We study phase separation in a three-component system whose microstructural evolution depends upon the reaction–diffusion interactions and to analyze the underlying configurational fields. This simulation portrays the interleaving between the reaction and diffusion processes and how the configurational tractions drive the motion of interfaces.

在高温高压下，岩石矿物之间的固体扩散和化学反应导致相变。向上扩散过程中的化学传递导致相分离，即旋节线分解。因此，为了描述出溶微观结构的粗化动力学，我们为多分量 Cahn-Hilliard 方程推导出了热力学一致的连续介质理论，同时考虑了多种化学反应并忽略了变形。我们的方法考虑了在扩展的 Larché-Cahn 框架内通过多组分含量平衡方程增强的微力的多重平衡。至于 Larché-Cahn 框架，我们将关于相场及其梯度的 Larché-Cahn 导数纳入理论。我们还以梯度能量系数的形式解释了由此产生的相场约束梯度的含义。此外，我们导出了一个配置平衡，其中包括与 Larché-Cahn 框架一致的所有相关配置字段。我们研究三组分系统中的相分离，其微观结构演变取决于反应-扩散相互作用，并分析潜在的构型场。该模拟描绘了反应和扩散过程之间的交织以及构型牵引力如何驱动界面运动。我们研究三组分系统中的相分离，其微观结构演变取决于反应-扩散相互作用，并分析潜在的构型场。该模拟描绘了反应和扩散过程之间的交织以及构型牵引力如何驱动界面运动。我们研究三组分系统中的相分离，其微观结构演变取决于反应-扩散相互作用，并分析潜在的构型场。该模拟描绘了反应和扩散过程之间的交织以及构型牵引力如何驱动界面运动。