Size effects of metals with real microstructures

Abstract

In this paper, the strength and deformation of small metals containing conventional microstructures, such as grain boundaries and second-phase precipitates, are discussed. In these samples, the microstructure imposes an internal length scale that may interplay with the extrinsic length scale due to the specimen size to affect strength and deformation in an intricate manner. For grain boundaries, their presence in a small specimen may significantly affect strength and yet, as a result of the limited specimen size, the effect is far from the Hall-Petch behavior for conventional polycrystalline metals. For precipitates, their interactions with the travelling dislocations in a specimen with confined size may lead to an interesting minimum strength behavior on increasing specimen size.