Multiscale Microstructural and Mechanical Characterization of Cu-Ni Binary Alloys Reduced During Hydrogel...

Area of Science:

• Materials Science
• Additive Manufacturing
• Metallurgy

Background:

• Hydrogel infusion-based additive manufacturing (HIAM) is a solid-state pathway for 3D structuring ceramics and alloys.
• HIAM allows for micro-scale precision and complex phase evolution through thermal treatments.

Purpose of the Study:

• To investigate the microstructural characteristics and mechanical properties of CuₓNi₁₋ₓ alloys produced by HIAM.
• To understand the relationship between composition, microstructure, and mechanical performance in HIAM-processed alloys.

Main Methods:

• 3D printing of metal ion-infused gels followed by thermal treatments.
• Microstructural characterization using electron microscopy and nanoindentation.
• Mechanical testing via uniaxial compression of micropillars.

Main Results:

• HIAM processing resulted in hierarchical composite microstructures with annealing twins and entrapped oxide nano-inclusions.
• Nanoindentation hardness was up to four times higher than bulk annealed CuₓNi₁₋ₓ.
• Composition-dependent "smaller is stronger" size effect observed, linked to reduction kinetics and defect density.

Conclusions:

• HIAM enables access to a rich microstructural landscape in alloys.
• The process allows for tuning of mechanical properties, offering a pathway to superior performance in additively manufactured materials.