3D Printed Copper-Nickel Alloy Achieves Nearly Fourfold Strength Increase at Caltech

Pasadena, CA – Researchers at the California Institute of Technology (Caltech) have announced a significant breakthrough in 3D printing, developing a novel method that allows for the creation of metal alloys with unprecedented control over their composition and properties. This new technique, dubbed Hydrogel-Infusion Additive Manufacturing (HIAM), enables the precise engineering of materials, including a copper-nickel alloy that exhibits nearly four times the strength of its conventionally produced counterparts.Unlike traditional methods that often struggle with homogeneity and precision, the HIAM process begins with the 3D printing of a hydrogel scaffold, which serves as a temporary blueprint. This scaffold is then infused with metal salts, allowing metal ions to infiltrate the structure. Subsequently, the hydrogel is burned away in a high-temperature calcination step, leaving behind metal oxides. The final crucial stage involves reductive annealing in a hydrogen-rich environment, where oxygen is stripped away, resulting in a pure, precisely shaped metallic alloy. This atom-by-atom control allows for on-the-fly adjustments to metal ratios.According to a tweet by Dylan Small, this innovation means that properties like strength and density can now be designed rather than estimated.> "Flip from a copper-heavy mix to a Cu12Ni88 alloy nearly four times stronger, without altering shape or tooling. Every property, from strength to density, is now designed, not guessed. This is metallurgy reinvented. Also a game changer for Aerospace applications."The enhanced mechanical resilience, particularly the significant strength increase seen in the Cu12Ni88 alloy, stems from the unique microstructure created by HIAM, including the formation of nanoscale oxide inclusions and highly uniform crystal structures. Julia R. Greer, the Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering at Caltech, emphasized that this method allows fine-tuning of chemical composition and microstructure, substantially enhancing mechanical resilience.This advancement holds immense potential for various high-demand applications. The ability to precisely tailor material properties opens doors for creating stronger, lighter components for aerospace, robust and biocompatible parts for biomedical devices like stents, and intricate elements for microelectronic mechanical systems (MEMS). The research, supported by entities including the U.S. Department of Energy and the National Science Foundation, was detailed in papers published in journals such as Small and Nature.