Lei Lu

Abstract

Synthesis and properties of gradient cell structured alloys

Understanding the fundamental of nanostructured heterogeneous materials, including multi-scale design criteria, interfaces, synergistic effects beyond the role and properties of mixtures, has become a major area of scientific inquiry. In this talk, we will present research progress on gradient nano-scaled dislocation-cell-structured (GDS) alloys fabricated by cyclic torsion technique. Compared with their homogeneous and heterogeneous counterparts, the GDS alloys exhibited a significantly improved strength–ductility combination at ambient and liquid nitrogen temperatures, as well as enhanced fatigue properties under both symmetric and asymmetric loads. The sample-level structural gradient, together with the nanoscale dislocation cells with low-angle boundaries, collectively contributes to a unique deformation mechanism associated with the formation of a high density of tiny stacking faults and the associated phase transformation.