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摘要
A constitutive model is derived for the viscoplastic response of a host medium driven by diffusion of guest atoms. With reference to the trapping concept, two states of a guest atom are distinguished: mobile and immobilized (due to alloying with the host matrix). Reaction-diffusion equations for the transport of mobile atoms and their trapping, as well as stress-strain relations for the mechanical behavior of the host material, are developed based on the free-energy imbalance inequality. The constitutive equations are applied to the analysis of stresses in a spherical electrode particle under insertion of lithium. Numerical simulation demonstrates the ability of the model to predict (i) formation of a sharp interphase between regions rich and poor in guest atoms, (ii) propagation of the interphase with a constant velocity, and (iii) size-dependent fracture of electrode particles.
- 出版日期2014-11
