Enhancing mechanical properties of metallic materials by architecting gradient structures

Abstract

Here, two types of gradient structures (GS), i.e. gradient dislocation structure (GDS) and gradient grain structure (GGS) are successfully constructed. Results indicate that the relationship between the strength and ductility of the samples with GDS and GGS is referred to as an inverse linear rule, which is in stark contrast to and superior to the banana-shaped strength-ductility trade-off dilemma in monolithic materials. In low-strength (σ_y∼400–550 MPa) range, plausible strength-ductility-toughness synergies can be achieved by both the GDS and GGS, however, in high-strength (σ_y∼550–750 MPa) range, much better strength-ductility-toughness combinations are presented by the GGS than those by the GDS. For the GGS, the formation of strong 〈110〉 fibre texture in the tensile direction is beneficial for enhancing the high strength-ductility-toughness synergy.