The thermodynamics and roughening of solid-solid interfaces

TL;DR

This paper analyzes the thermodynamics and stability of solid-solid interfaces under stress, revealing how phase transition order influences interface roughening and the formation of finger-like structures during evolution.

Contribution

It introduces a thermodynamic framework for interface transformation dynamics and performs stability and numerical analyses to understand interface roughening.

Findings

Interface stability depends on phase transition order.

Small density contrasts can cause finger-like structures.

Numerical simulations show interface roughening under stress.

Abstract

The dynamics of sharp interfaces separating two non-hydrostatically stressed solids is analyzed using the idea that the rate of mass transport across the interface is proportional to the thermodynamic potential difference across the interface. The solids are allowed to exchange mass by transforming one solid into the other, thermodynamic relations for the transformation of a mass element are derived and a linear stability analysis of the interface is carried out. The stability is shown to depend on the order of the phase transition occurring at the interface. Numerical simulations are performed in the non-linear regime to investigate the evolution and roughening of the interface. It is shown that even small contrasts in the referential densities of the solids may lead to the formation of finger like structures aligned with the principal direction of the far field stress.