Multiwell phase-field model for arbitrarily strong total-spreading case

In this paper, we revisit a classical multiwell phase-field model in the context of β – ω phase transformations in titanium alloys. We propose a novel model by adjusting the algebraic part of the traditional interfacial free energy in a way that allows for a relaxation of the standard well-posedness constraints on surface tensions in the total-spreading case. The proposed adjustment effectively prevents the formation of a mixed ω – ω state in the resulting phase-field continuum model, aligning with the crystallographic impossibility of such a configuration in reality. We further introduce a chemical energy mixing function that preserves the local stability of purely two-phase β – ω configurations, preventing the spontaneous appearance of additional phases. We illustrate the advantages of the novel model through numerical simulations in one, two and three spatial dimensions and outline a pathway toward a more realistic model of β – ω transition model in titanium alloys.