On the Design of Ultra-High-Temperature Material Systems

In this paper an approach was proposed for the design of ultra-high-temperature material (UHTM) systems comprising a metallic UHTM substrate plus an environmental coating, based on past and on-going research in the author's research group and in other research groups. The environmental coating, which was considered in order to discuss the design approach, was composed of a multi-material (multilayer) or functionally gradient bond coat, a thermally grown oxide, and a top coat. Issues that research must consider were identified. The complexity of UHTM systems was discussed, matters that design must take into account and the role of synergistic metallurgy were considered, and the importance of the environment was disclosed. The question of how the properties and behaviour of a UHTM system emerge was discussed.