The Pursuit of the Small: From Grain-Boundary Cavities to Nanocrystalline Metals

The following article is based on the Von Hippel Award presentation given by JuliaWeertman of Northwestern University on December 3, 2003, at the Materials ResearchSociety Fall Meeting in Boston.Weertman received the award for "her lifelong exceptionalcontributions to understanding the basic deformation processes and failure mechanismsin a wide class of materials, from nanocrystalline metals to high-temperature structuralalloys, and for her inspiring role as an educator in materials science. It has been saidthat "the best things come in small packages," and that is certainly in Weertman's mind inthis presentation. She has spent much of her career "in pursuit of the small. In this article,she first looks back at her experiences studying grain-boundary cavities and life in thespaces between grains. She then fast-forwards to modern work on nanocrystallinemechanical behavior, confirming that such nanocrystalline materials are indeed strong,but also brittle. Some of her experiences in studying these phenomena are also described