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Materials Science at Oregon State University

Annealing Twin Boundary Formation in low SFE FCC Metals

Date: Thursday, Apr 16th
Presenter: David P. Field, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA

Abstract


Substantial research has been performed for evaluation of grain boundary engineered (GBE) materials where a high fraction of “so-called” special boundaries is required. It has been shown that a high concentration of twin boundaries in a material improves the material properties for many different applications, but there remain somewhat conflicting theories on the development of twin boundaries. Annealing twin boundary evolution was observed by ex-situ and in-situ EBSD measurements on Cu and Ni. It was observed that there are many mechanisms for twin boundary formation during recrystallization of these structures. One mechanism involved a change in orientation of the grain to promote further recrystallization after growth of a recrystallizing grain had stagnated. It is shown that twin boundaries will form that increase the driving force for growth, thereby lowering the overall energy of the system. This confirms at least one theory for twin boundary formation.

Bio:
David P. Field received a Ph.D. from Yale University in 1991 in Mechanical Engineering. From 1990 to 1994 he was employed as a senior engineer at Alcoa Technical Center near New Kensington, PA. In 1994, he joined with 2 colleagues in founding TexSEM Laboratories where he was Director of Technology until he joined WSU as an Assistant Professor of Mechanical and Materials Engineering in August, 2000. He served as the Interim Director of the School of Mech and Matls Engineering from 2012-2013 before being appointed to his present position as Associate Dean for Research and Graduate Studies of the Voiland College of Engineering and Architecture in 2013. He has given lectures and workshops worldwide and has been a visiting professor at institutes in France and India. He is a fellow of ASM International, has published over 150 journal articles, and has edited several books on topics such as Friction Stir Welding, Reliability of Microelectronics, Textures in Thin Films, and Electron Backscatter Diffraction.