In response to the grave and escalating threat of climate change, the US Department of Energy has announced a series of ambitious Energy Earth Shot Initiatives. These target an 80% reduction in the cost of clean hydrogen by 2030 and net-zero carbon emissions by 2050. The first of the initiatives focuses on establishing a green hydrogen-powered grid. Hydrogen is expected to play an important role in the creation of a carbon neutral/positive hybrid network for energy production, storage, and distribution. Two key technological challenges are the repurposing of existing infrastructure, such as land-based gas turbines for hydrogen combustion, and accelerating deployment of new infrastructure, including far-offshore wind farms that can generate hydrogen for energy storage and transfer, helping to address energy demand intermittency and decentralization challenges.

As such, there is an urgent need to develop structural and tribological materials with greater resilience to harsh environments including hydrogen-containing fluids at extremes of temperature, which can range from liquid hydrogen (20 K) in cryogenic pumps and pressure vessels to >1500 K in gas turbines. High-entropy alloys (HEAs) and additive manufacturing (AM) methods are two areas of intensive research and a focus of this presentation. Highlights will be presented from ongoing work at Ames National Laboratory, in collaboration with other national laboratory, academic, and industry partners, including the use of AM as a means of processing refractory HEA and other traditionally difficult-to-manufacture alloys. The development and use of rapid mechanical property characterization methods will also be discussed, as well as how these are enabling alloy discovery and process optimization, including for HEAs, which are multi-element alloys that present an extraordinarily challenging departure from traditionally dilute compositions. Additionally, examples of new fundamental insights about structure-property relationships for compositionally and structurally complex systems like HEAs and metallic glasses will be presented.