Simulations of Interfacial Connectivity

1. Fraction of ‘perfect’ quadruple nodes Fraction of damage- resistant interfaces Fraction of damage-resistant interfaces Development of Percolation Theory for Interface Networks in MaterialsChristopher A. Schuh, Materials Science and Engineering, MIT, DMR-0346848 Around quadruple nodes, where four grains and six interfaces meet, our simulations show non-random coordination of special, or damage-resistant, interfaces, Materials usually contain internal interfaces, some of which can be weak-links that compromise properties. By tailoring the connectivity of such interfaces, some materials properties can be improved ten-fold. Simulations Random Simulations of Interfacial Connectivity We use Monte Carlo computer simulations to explore the connectivity of interfaces assembled into networks. The simulations reveal that interfaces are arranged in non-random patterns… And the percolation threshold for damage paths is non-random as well.

2. Development of Percolation Theory for Interface Networks in MaterialsChristopher A. Schuh, Materials Science and Engineering, MIT, DMR-0346848 • Our research involves education at several levels: • Megan Frary is the lead graduate student on the project (MIT), developing simulation techniques to study grain boundary networks. She will earn a Ph.D. in 2005. • Christopher Ng is an MIT undergraduate supervised by Megan Frary, working on the experimental validation of our models. He is pursuing a research B.S.-thesis. • Suzanne Nichols is an undergraduate from the University of Louisville, who visited the group as part of our outreach program for the summer of 2004. She helped develop codes for analyzing network topology. Our research from the past year has been disseminated in an article in Physical Review B (v69, 134115), and in a second article submitted for publication. Additionally, a symposium on “Interfacial Engineering for Optimized Properties” was co-organized by the PI at the Spring 2004 meeting of the Materials Research Society.