The thermal instability of nanocrystalline materials - an experimental case study of microstructural evolution in ball-milled iron

Abstract

Manifesting superior properties compared to their coarser-grained conventional counterparts, nanocrystalline materials are attracting growing attention in the areas of basic research and industrial application. However, the advantages of these materials - which relate to their exceptionally high number density of grain boundaries - come at the cost of an inherent instability with respect to grain growth. In order to develop strategies for retaining grain-size-related property enhancements, the nature and mechanisms of grain growth occurring in nanocrystalline materials must be understood thoroughly. This thesis represents an effort to carry out a comprehensive experimental investigation of thermally induced microstructural evolution in nanocrystalline alpha-Fe prepared by mechanical attrition.