Dual-scale chemical ordering for cryogenic properties in CoNiV-based alloys

Area of Science:

• Materials Science
• Metallurgy
• Nanotechnology

Background:

• Mechanical properties of metallic materials degrade at cryogenic temperatures, challenging low-temperature infrastructure.
• Developing materials with improved strength and ductility for cryogenic environments is crucial.

Purpose of the Study:

• To introduce a dual-scale atomic-ordering nanostructure in a CoNiV-based alloy.
• To enhance the synergy of strength and ductility in metallic materials at low temperatures.

Main Methods:

• Fabrication of a CoNiV-based alloy with a dual-scale atomic-ordering nanostructure.
• Characterization of subnanoscale short-range ordering and nanoscale long-range ordering domain densities.
• Mechanical testing at cryogenic temperatures (87 K).

Main Results:

• Observed an ordering-induced increase in dislocation shear stress and more rapid dislocation multiplication.
• Demonstrated a strength-elongation product of 76 GPa-% and a yield strength of ~1.2 GPa at 87 K.
• The dual-scale ordering outperformed materials lacking this hierarchical structure.

Conclusions:

• Dual co-existing chemical ordering significantly impacts mechanical properties of complex alloys at low temperatures.
• Controlling these ordering states offers a pathway to enhance material performance for cryogenic applications.
• The developed nanostructure provides a promising solution for demanding cryogenic environments.