Digital Design of a Lightweight and Low-Cost UHS Steel

A new generation of high-performance, ultra-high strength (UHS) steelsSteel are required for lightweight applications at low prices. Traditionally, the outstanding properties of maraging (martensite-aging) steelsSteel emerge from semi-coherent nanoprecipitation in a martensitic matrix. However, coherency strains originating from the semi-coherent precipitates promote crackCrack initiation under load and thus inevitably reduce ductility. Multiple authors have suggested as a solution a highly-dense nanoprecipitation of Ni(AlAl,Fe) coherent precipitates with minimal latticeLattices misfit and validated the idea experimentally. In this work, we computationally designed, from processing to performance, a UHS steelSteel composed of Fe-Ni-Al-Mo with a higher specific yield strength and much lower price. Several foundational computational tools within the ICMEICME framework were adopted to design the steelSteel, including Thermo-Calc, TC-PRISMA, DICTRA, and TC-Python.