Biomedical Engineering Reference
In-Depth Information
5
Multiscale modeling of the structure and
properties of ceramic nanocomposites
V . TOMAR , Purdue University, USA
Abstract: One of the most recent developments in ceramics has been the
distribution of multiple phases in a ceramic composite at the nanoscopic
length scale. An advanced nanocomposite microstructure such as that of
polycrystalline silicon carbide (SiC)-silicon nitride (Si
3
N
4
)
nanocomposites contains multiple length scales with grain boundary
thickness of the order of 50 nm, SiC particle sizes of the order of 200-
300 nm and Si
3
N
4
grain sizes of the order of 0.8-1.5
μ
m. Designing the
microstructure of such a composite for a targeted set of material
properties is, therefore, a daunting task. Since the microstructure
involves multiple length scales, multiscale analyses based material design
is an appropriate approach for such a task. With this view, this chapter
presents an overview of the current state of the art and work performed
in this area.
Key words: ceramic nanocomposites, microstructure, multiple length
scales, multiscale modeling.
5.1
Introduction
Over the past half century, ceramics have received significant attention as
candidate materials for use as structural materials under conditions of high
loading rates, high temperature, wear, and chemical attack that are too
severe for metals. However, the inherent brittleness of ceramics has
prevented their wide use in different applications. Significant scientific
effort has been directed towards making ceramics more flaw-tolerant
through design of their microstructures by:
