| Abstract Scope |
In this study, a new lightweight quadruplex steel is achieved through duplex ordering transformations. The initial materials is a duplex lightweight steel, characterized by a microstructure of austenite and D03 intermetallic compounds (IMCs). During aging process, the emergence of L'12 ordering in austenite brings about significant strengthening from Kappa carbide. Concurrently, B2 ordering takes place in the D03 IMC domains, producing a softening effect within the B2-D03 IMC domains. Thus, the duplex ordering can reduce strength gap between austenite and IMC domain, favoring deformation homogeneity. Although stacking faults and deformation twins are reduced during plastic deformation, strain hardening by micro-shear bands is observed since yielding at 1500 MPa. Therefore, this novel lightweight steel exhibits a high yield strength of over 1500 MPa, ultimate tensile strength of 1700 MPa, and a total elongation of 16%. The duplex ordering paves the way for strong and ductile lightweight steels. |