TABLE OF CONTENTS Functionally graded materials (FGMs) are multifunctional materials, which contain a spatial variation in composition and/or microstructure for the specific purpose of controlling variations in thermal, structural or functional properties. Also in the ceramics composites field, a wide range of functionally graded (FG) ceramics are available. Hence, a possible classification of the different classes is made in this chapter.
Compared to homogeneous materials a lot of advantages exist. However, there would be little point in developing such a FGM material unless it could compete commercially with existing homogeneous ceramic components currently on the market. A wide variety of processing routes are available for FGMs and it is important to choose the right processing technique for the right application. Therefore, a large part of this chapter deals with the processing of FGM, more specifically for bulk FGMs.
The gradient composition in FGMs not only results in a spatial variation in properties but will also generate residual stresses, which will affect the mechanical properties. One of the potential advantages of FG components is the positive influence of compressive residual surface stresses on the strength and wear resistance. A correct design of the gradient for an optimal distribution of the residual stresses is therefore important, as discussed in this chapter.
Special attention will be given to structural FGM applications, where the operating conditions are severe. More specifically, alumina/zirconia and WC/Co FGM components will be discussed.
As a...
