2001 Volume 42 Issue 3 Pages 502-508
Nanocrystalline materials with a grain size of ≤100 nm are expected to be strong and hard and at the same time exhibit improved ductility/fabricability in comparison to their coarse-grained counterparts. Even though this has been shown to be possible in some nanocrystalline ceramic materials, there have been concerns on the validity of these results because of inadequate densification of the samples. It has also been suggested that achievement of nanostructures may not be desirable to ductilize the intermetallics. This article presents an overview of the fracture behavior of materials as a function of grain size, and shows that based on the observations that the strain-rate sensitivity and fracture toughness of nanostructured materials are higher than in their coarse-grained counterparts, achievement of nanocrystallinity in materials (including intermetallics) can lead to improved ductility and hence is a profitable route to investigate.
