A Perspective on Modeling Materials in Extreme Environments: Oxidation of Ultrahigh-Temperature Ceramics
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A Perspective on
Modeling Materials in Extreme Environments: Oxidation of UltrahighTemperature Ceramics
Angelo Bongiorno, Clemens J. Först, Rajiv K. Kalia, Ju Li, Jochen Marschall, Aiichiro Nakano, Mark M. Opeka, Inna G.Talmy, Priya Vashishta, and Sidney Yip Abstract The broader context of this discussion, based on a workshop where materials technologists and computational scientists engaged in a dialogue, is an awareness that modeling and simulation techniques and computational capabilities may have matured sufficiently to provide heretofore unavailable insights into the complex microstructural evolution of materials in extreme environments. As an example, this article examines the study of ultrahigh-temperature oxidation-resistant ceramics, through the combination of atomistic simulation and selected experiments. We describe a strategy to investigate oxygen transport through a multi-oxide scale—the protective layer of ultrahightemperature ceramic composites ZrB2-SiC and HfB2-SiC—by combining first-principles and atomistic modeling and simulation with selected experiments. Keywords: ceramic, oxidation, oxide, simulation.
Introduction In its recent report, the U.S. President’s Information Technology Advisory Committee declared, “Computational science—the use of advanced computing capabilities to understand and solve complex problems—has become critical to
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scientific leadership, economic competitiveness, and national security.”1 This recognition of the emerging power of computation is but one of several current challenges to the scientific community2 to identify specific applications where high-
performance computing can be exploited through science-based modeling and simulation for societal benefits. In this article, we examine one such problem, the study of ultrahigh-temperature oxidationresistant ceramics, through the combination of atomistic simulation and selected experiments. Oxidation is a well-known bottleneck in the development of high-temperature materials for aero-propulsion and hypersonic flight applications. While various materials selection and processing routes have been investigated experimentally, basic understanding of oxygen transport through the complex oxide scale microstructure of an ultrahigh-temperature ceramic (UHTC) remains elusive. Given the advances in large-scale computing, along with methods of multiscale materials modeling,3 an exploration of an integrated computational– experimental approach to assist the further development of UHTCs seems timely. High-temperature oxidation of ceramics involves sufficient complexity in transport kinetics and microstructural evolution to qualify as a prototypical challenge to the prediction of material response in an extreme environment. This is a problem of considerable practical importance which largely has not been addressed by the computational materials community. Discussions at a recent workshop4 indicated that state-of-the-art UHTC development could benefit from a synergistic collaboration, one that brings together the critical-issue a
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