Published September 11, 2025 | Version Supplemental Material
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Multiscale Microstructural and Mechanical Characterization of Cu–Ni Binary Alloys Reduced During Hydrogel Infusion‐Based Additive Manufacturing (HIAM)

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon Dartmouth College

Abstract

AbstractHydrogel infusion‐based additive manufacturing (HIAM) is a chemically versatile solid‐state processing pathway that allows 3D structuring of ceramics and alloys with micro‐scale precision. Using thermal treatments of 3D‐printed metal ion‐infused gels, this process generates intricate microstructures throughout their complex phase evolution. Through investigation of the HIAM‐produced CuxNi1-x alloy system, substantial grain growth after reduction is shown to drive the formation of numerous annealing twins and entrap unreduced oxide nano‐inclusions, resulting in hierarchical composite microstructures. These features appear to elevate the average nanoindentation hardnesses by up to four times that of bulk annealed CuxNi1-x. Uniaxial compression of micropillars milled from individual grains reveals composition dependence on the scaling of the "smaller is stronger" size effect. This compositional dependence of deformation mechanisms arises from changes in reduction kinetics which influence the density of inclusions and voids developed by the HIAM process. This work highlights the rich microstructural landscape accessible to HIAM‐produced alloys and provides a useful pathway for the characterization and tuning of superior mechanical performance in additively manufactured alloys.

Acknowledgement

J.R.G. gratefully acknowledges the financial support from the U.S. Department of Energy, Office of Science, Basic Energy Sciences (DE-SC0016945). T.T.T. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1745301. The authors acknowledge assistance from Dr. Mingjie Xu and the use of facilities and instrumentation at the UC Irvine Materials Research Institute (IMRI), which is supported in part by the National Science Foundation through the UC Irvine Materials Research Science and Engineering Center (DMR-2011967).

Copyright and License

© 2025 Wiley-VCH GmbH

Supplemental Material

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smll70067-sup-0001-SupMat.docx 2.5 MB

Supporting Information

smll70067-sup-0002-MovieS1.avi 32.1 MB

Supplemental Movie 1

smll70067-sup-0003-MovieS2.avi 28.8 MB

Supplemental Movie 2

smll70067-sup-0004-MovieS3.avi 18 MB

Supplemental Movie 3

Data Availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Contributions

T.T.T. synthesized samples, conducted TEM experiments, and performed nanopillar experiments. R.A.G. and T.T.T. carried out nanoindentation, performed EBSD measurements, and analyzed data. All authors contributed to writing the manuscript and have given approval to the final version of the manuscript.

Conflict of Interest

The authors declare no conflict of interest.

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Additional details

Identifiers

Funding

UC Irvine Materials Research Institute
DMR‐2011967
Office of Basic Energy Sciences
DE-SC0016945
National Science Foundation
Graduate Research Fellowship DGE-1745301

Dates

Available
2025-07-23
Published online

Caltech Custom Metadata

Caltech groups
Kavli Nanoscience Institute, Division of Engineering and Applied Science (EAS)
Publication Status
Published