phase transformation; interface migration; bulk diffusion; Onsager extremal thermodynamic principle
Physical analysis of phase transformation of materials consisting from several (both substitutional and interstitial) components, coming from the Onsager extremal thermodynamic principle, leads, from the mathematical point of view, to a system of partial differential equations of evolution type, including certain integral term, with substantial differences in particular phases ($\alpha$, $\gamma$) and in moving interface of finite thickness ($\beta$),
in whose center the ideal liquid material behaviour can be detected. The numerical simulation of this process in MATLAB
is able to explain some phenomena (e.g. the interface velocity as a function of temperature) better than known simplified models assuming the sharp interface
and additional boundary and transfer conditions.