An overview of research on functionally graded materials for thermal stress relaxation

The original concept of Functionally Graded Materials (FGMs) for thermal stress relaxation was proposed in Japan in 1984, and research activities on FGMs have expanded throughout the world in the last two decades. Much effort covering the design, synthesis, testing & evaluation and integration of FGMs as well as their application have been done. Two kinds of small thrusters for a reusable rocket plane were made and demonstrated their superiority. Research activities on FGMs in Japan have stimulated those of other counties and some components of rocket engines made of FGMs were recently fabricated and tested. Subjects for realizing FGMs in practical use are finally discussed.