Simulating microgalvanic corrosion in alloys using the PRISMS phase-field framework

Abstract

In this prospective paper, we first review the existing simulation tools to simulate microgalvanic corrosion during free immersion. Then, we describe a recently developed application that employs PRISMS-PF, an open-source, high-performance phase-field modeling framework. The model employed in the application accounts for the electrochemical reaction at the metal/electrolyte interface and ionic migration in the electrolyte to determine the evolution of the corrosion front. We present the implementation details for the application and discuss its features such as super-linear parallel scaling performance for a sufficiently large system. Finally, we demonstrate the capability of the application by simulating corrosion of the matrix phase of an alloy near a secondary phase particle in two and three dimensions. Graphical abstract

Understanding the Effect of Electrochemical Properties and Microstructure on the Microgalvanic Corrosion of Mg Alloys via Phase-Field Simulations

“…We employ the phase-field model 22 that describes the evolution of the anodic phase/electrolyte interface due to microgalvanic corrosion with a cathodic phase under the assumption that the electrolyte is well-stirred and under the condition of free immersion. The model has been described in Ref.…”

“…The model has been described in Ref. 22, and therefore we only present a brief description of the model equations here, along with the descriptions of the variables and symbols summarized in Table I.…”

“…27 These assumptions are in line with previous modeling studies. [20][21][22] Under these assumptions, where diffusive and convective contributions are absent, the ionic flux arises solely from the migration current, i.e., κ = − ∇Φ i .…”

“…e Finally, the resulting equation is formulated using the Smoothed Boundary Method (SBM) 28 to incorporate the flux boundary conditions at the metal/electrolyte interface arising from the electrochemical reaction and the zeronormal-flux boundary conditions at domain boundaries, as derived in a previous work: 22 Table I. List and description of the variables and symbols used in the model equations.…”

“…Several experimental and modeling studies have examined the roles of the aforementioned factors on the corrosion behavior of Mg alloys, including the effect of alloying elements 3,4,16,17 and the microstructure. 2,8,[10][11][12][13][14][15][18][19][20][21][22] Many alloys form a two-phase system: one is the solute-rich β phase (which is the minority/second phase), and the other is the solute-depleted α phase. In most Mg alloys, a microgalvanic couple is formed between the β phase that acts as a cathode and the α phase that acts as an anode.…”