Synthesis of Bulk Nanostructured DO22 Superlattice of Ni3(Mo, Nb)‎ with High Strength, High Ductility, and High Thermal Stability

Abstract EN

We show that a bulk nanostructured material combining high strength, high ductility, and high thermal stability can be synthesized in a Ni-Mo-Nb alloy with composition approaching Ni3(Mo, Nb).

By means of a simple aging treatment at 700°C, the grains of the parent face-centered cubic phase are made to transform into nanosized ordered crystals with DO22 superlattice maintaining a size of 10–20 nm after up to 100 hours of aging and corresponding room-temperature yield strength of 820 MPa and tensile ductility of 35%.

Deformation of the superlattice is found to predominantly occur by twinning on {111} planes of the parent phase.

It is concluded that, although the respective slip systems are suppressed, most of the twinning systems are preserved in the DO22 superlattice enhancing the ductility.