5th International High Manganese Steel Conference - HMNS 2022

Maraging steels have been widely used for the industrial application needed high strength materials such as aerospace technology and military industry. The corresponding steel is generally composed of substitutional elements such as 17-19 % Ni (in weight percent), and 8-12 % Co, 3-5 % Mo and 0.2-1.8 % Ti, and it contains a small amount of C (< 0.03 %). After hot rolling and subsequent aging, the steels reveal the α' martensitic matrix with intermetallic nanoprecipitates such as Ni3Mo (D0a-type), Ni3Ti (D024-type), Ni3Al (L12-type), and Fe2Mo (C14-type), resulting in a high yield strength of over 1.4 GPa and a high tensile strength of over 1.6 GPa. However, despite its remarkable mechanical response, the relative high materials cost of the steels driven by expensive alloying (e.g., a high amount of Ni, Mo, and Co) hinders the mass production. Therefore, in the present study, we proposed the new alloy design concept of maraging steel with the merit of materials cost, and the microstructural evolutions and mechanical response of the steel are systematically investigated. Regarding the alloy composition, the high Ni content in conventional maraging steel was partly replaced to Mn content, and the ~4 wt.% of Al was added to form an intermetallic nanoprecipitate (e.g., NiAl) and to reduce the weight of alloy.