A Kinetic Phase-Field Model of Diffusion Bonding: A Nonlocal Approach to Interface Coalescence

TL;DR

This paper introduces a nonlocal kinetic phase-field model for diffusion bonding that allows control over interface coalescence, enabling the simulation of processes where interfaces remain distinct under specific thermodynamic conditions.

Contribution

The paper develops a novel phase-field model using a geometric conservation law and nonlocal curvature criteria to control interface merging, extending the modeling capabilities for diffusion bonding.

Findings

Model enables control over interface coalescence.

Simulations demonstrate adjustable bonding kinetics.

Allows interfaces to remain distinct under certain conditions.

Abstract

Conventional phase-field models often drive solid-solid interfaces to coalesce when in close proximity. This feature limits their use for processes like diffusion bonding, where the interfaces might need to remain distinct under certain thermodynamic conditions. We develop a kinetic phase-field model to address this problem, using an evolution equation based on a geometric conservation law for interfaces, rather than the gradient descent evolution that is typical in phase-field modeling. This formulation enables us to specify complex kinetic laws, and we use this to incorporate a physically-motivated geometric criterion to control interface merging. This criterion, based on nonlocal higher-derivative curvature invariants of the phase field, can be temperature-dependent, allows for a range of behaviors from complete coalescence to the preservation of distinct boundaries. Simulations show controlled bonding kinetics, demonstrating capabilities that are not available with existing methods for modeling interfaces that must remain distinct under given thermodynamic conditions.