WORLDWIDE TRENDS IN FUNCTIONAL GRADIENT MATERIALS RESEARCH-AND-DEVELOPMENT

This review concerns a new class of advanced materials, known as structural and functional gradient materials (FGMs), characterized by compositional and/or microstructural gradation over macroscopic/microsopic distances. This constitutional gradation can be tailored for specific requirements. The related properties are not only mechanical (static and dynamic strength, hardness, wear resistance), but also thermal (heat conductivity and isolation), chemical (corrosion and oxidation resistance), etc. These gradients are introduced intentionally and are quantitatively controlled in order to optimize materials properties for use in real environments by place-to-place control of composition and microstructure. A short theoretical description of FGMs, their processing methods, applications, etc. is presented, with analysis of their current state of development in the world and in Europe in particular. Future possibilities and trends are also discussed in the light of the coming Third World Symposium on FGMs at Lausanne, Switzerland.