Physical Metallurgy and Mechanical Properties of Ultrahigh Strength Steels

Ultrahigh strength steels (UHSSs) are crucial for heavy load‐bearing components in aerospace and automotive applications, such as aircraft landing gears, crankshafts, and fasteners. This review presents recent advancements in various categories of UHSSs, including medium/high‐carbon low‐alloy steels, secondary hardening steels, and maraging steels. By analyzing alloy design, microstructural engineering, and strengthening strategies, it highlight novel approaches to mitigate trade‐offs between strength and ductility. Special emphasis is placed on cutting‐edge developments in innovative processing techniques, including thermomechanical treatments and additive manufacturing, and their impact on multiscale microstructures and mechanical properties of UHSSs. Furthermore, it outline future directions for UHSS research, including data‐driven alloy design, hydrogen embrittlement mitigation, enhancing thermal stability and mechanical properties at elevated temperatures, and optimizing comprehensive material properties. This review provides useful insights into the fundamental understanding and future development of UHSSs for technological applications.