2. Material classes and process types

Since the choice of materials depends essentially on the application for which they are intended and the process by which they are to be used, it is important first of all to give two brief overviews:

• one, the major classes of materials and the generic properties that characterize them ;

• the other, the main processes used to produce parts and finished products from these materials.

These two reviews naturally lead to more detailed inventories of materials' properties of use on the one hand, and of process characteristics on the other, as well as of the obligatory interactions between a material, the product for which it is intended and the processing method used.