Chapter 1 - Introduction

Summary

In the last 25 years there has been a strong movement to use ceramics in new technological applications and a key facet of this work has been directed at understanding the mechanical behavior of these materials. First, let us consider the various technological functions of ceramics as shown in Table 1.1. The diverse properties of ceramics are not always appreciated. For structural functions, adequate mechanical properties are of prime importance. Ceramic materials that are considered for these applications are termed structural ceramics. In some cases, such as engine parts, the choice is based on their high-temperature stability and corrosion resistance. These factors imply the engine temperature could be raised, making the overall performance more efficient. Unfortunately, ceramics can be brittle, failing in a sudden and catastrophic manner. Consequently, there has been a strong emphasis on understanding the mechanical properties of ceramics and on improving their strength, toughness and contact-damage resistance. Indeed, it is appropriate to state that there has been a revolution in the understanding of these properties and the associated research has led to the discovery of new classes of structural ceramic materials.

It is important to realize that mechanical properties can also be critical in non-structural applications. For example, in the design of the thermal protection system of the space shuttle, highly porous, fibrous silica tiles are used.