Designing Corrosion Resistant High Entropy Alloys Via Chlorine Susceptibility Index

Abstract

In this poster presentation, first principle density functional theory (DFT) implemented in the Vienna Ab-initio Simulation Package (VASP) is coupled with Chlorine Susceptibility Index (CSI) to guide the design of high entropy alloys (HEA) for materials employed in marine environment. On the atomic scale, elements within HEAs are randomly distributed throughout the alloy. This disordered crystalline state renders the investigation of all possible combinations impossible for DFT calculations. The CSI methodology developed by Dr. Huibin Ke in the Taylor group can be applied here to circumvent this issue [1]. The first successful CSI model for alloy systems was derived based on the special quasi-random structure approach[2] utilized for the study of Ni-Cr 22 alloy[3] and uses the first-principles thermodynamics approximation that allows the prediction of preferred chemisorption states in mixed media as a function of pH, electrochemical potential and chloride concentration[4]. Herein, we apply this method in search for combinations of elements that can provide the best corrosion resistance, under constraints of satisfying the high entropy alloy predictors of configurational entropy, valence electron concentration, atomic size difference[5] as well as cost efficiency (cost should be on par with Stainless Steel 304). Performance predictions will be compared with a parallel experimental program involving alloy synthesis, structural characterization and electrochemical characterization of the corrosion performance [6]. Reference: [1] H. Ke and C.D. Taylor, Chloride Susceptibility Index (CSI): An ab initio based corrosion resistance indicator, Research in Progress, NACE (2019), Nashville, TN [2] S. Wei, L.G. Ferreira, J.E. Bernard, A. Zunger, Electronic properties of random alloys: Special quasirandom structures, 42 (1990). [3] A.J. Samin, C.D. Taylor, First-principles investigation of surface properties and adsorption of oxygen on Ni-22Cr and the role of molybdenum, Corros. Sci. 134 (2018) 103–111. doi:10.1016/j.corsci.2018.02.017. [4] C.D. Taylor, S. Li, A. Samin, S. Li, A. Samin, Oxidation versus salt-film formation: Competitive adsorption on a series of metals from first-principles, Electrochim. Acta. (2018). doi:10.1016/j.electacta.2018.02.150.This. [5] M.C. Gao, J.-W. Yeh, P.K. Liaw, Y. Zhang, eds., High-Entropy Alloys: Fundamentals and Applications, Springer, 2016. doi:10.1007/978-3-319-27013-5_12. [6] A. Panindre, G.B. Viswanathan, S. Li, C. D. Taylor, G.S. Frankel, The effect of intermediate temperature anneal on the corrosion properties of a High Entropy Alloy, NACE Conference 2019, Nashville, TN, USA.