Some principles for making graded materials

A brief survey is presented of research on making certain types of graded m aterial that have not yet been widely used. In particular, attention is giv en to graded materials involving phase transitions, vitreous ceramics, and single crystals. There is a discussion of making graded composites by direc tional crystallization. There is also a discussion of making products from graded materials by the rise of prototyping technology.