Architected superalloys: A pathway to lightweight high temperature materials

Abstract

Materials for high temperature applications – for example rocket engines – are often metallic and therefore tend to suffer from high density when used in their monolithic form. The root cause of this dilemma is the solid-state physics causing the low rates of thermally-activated processes such as diffusion and creep, it also confers the very high density. Using the nickel-based superalloys as an exemplar, we demonstrate here that this dilemma in high temperature materials can be defeated by designing open cellular structures – leveraging recent progress in new alloys designed specifically for additive manufacturing. The resulting low-density architected materials exhibit optimal stretch-dominant or bend-dominant behaviour at high temperatures, as exemplified by regular honeycomb structures which are built. Thus, as well-behaved materials these findings open up new design possibilities for high-temperature applications where low density is particularly needed.