12 - Applications

Summary

The commercial exploitation of MMCs is now becoming significant. A number of applications have emerged in which their advantages over traditional materials are such that full-scale substitution is now taking place. In other instances more detailed engineering data are needed and/or manufacturing or design problems need to be resolved. In surveying the scope for commercial usage, it should be recognised that in many cases it is the potential for achieving a desirable suite of properties which makes MMCs so attractive. Nevertheless, it is helpful to examine the potential advantages in turn, and this is done in the first part of the current chapter, with illustrative examples of usage mentioned where appropriate. In the second part, attention is concentrated on several specific applications for which MMCs are either already in use or are undergoing commercialisation.

Engineering properties of MMCs

Stiffness enhancement

Potential for the enhancement of stiffness, and specific stiffness, is one of the most attractive features of MMCs. Stiffness is a critical design parameter for many engineering components, as the avoidance of excessive elastic deflection in service is commonly the overriding consideration, and the incentive to achieve even a modest increase is often very high indeed. This is the case for many rotating parts, support members, structural bodywork, etc., for which metals offer essential combinations of toughness, formability, environmental stability and strength. However, with very few exceptions (Al–Li being the prime example), there is no scope for increasing the stiffness of a metal by minor additives or microstructural control.