Exploration of the processing scheme of a novel Ni(Fe, Al)-maraging steel

NiAl-precipitate-strengthening steels, utilizing the inexpensive and lightweight element Al instead of Co and Ti to form strengthening precipitates, have cost and weight advantages over conventional maraging steels. However, such steel can hardly achieve ultimate strength above 1600 MPa if without co-precipitation of other precipitated phases. The goal of current work is to explore a processing scheme that can further improve the strength over 1600 MPa without sacrificing ductility and explain the mechanism. With the optimization of processing scheme, Ni(Fe, Al)-maraging steel, as a new type of such steel, achieves strength of up to ~2.1 GPa and elongation of 9.31%. The strengthening mechanism is discussed and concluded based on the results of tensile tests and microstructural characterizations. The key factor of further enhancing the strength and ductility simultaneously is given.