EAGER: Scalable Synthesis of Twinned Metals and Alloys

About This Grant

NON-TECHNICAL SUMMARY This research explores how to produce a new class of advanced metals that are both exceptionally strong yet very formable and ductile. In most materials, increasing strength typically makes them more brittle, while increasing ductility often reduces their strength. This tradeoff limits performance in critical structural applications. A special class of materials known as nanotwinned metals overcomes this limitation by reorganizing the atomic structure to form nanoscale layers that improve both strength and deformability. However, current manufacturing methods can only produce these beneficial structures in thin films or small-scale components. This project investigates two advanced manufacturing techniques designed to engineer nanotwinned structures within bulk materials while enabling their formation across larger volumes. The goal is to establish science-based protocols for the scalable production of nanotwinned metals and alloys. This project is actively seeking to unlock a new generation of high-performance structural materials for use in extreme environments. These outcomes have wide-reaching impacts in aerospace, energy systems, and advanced manufacturing, while also supporting the training of future engineers and scientists in cutting-edge materials technologies. This effort is contributing to the national workforce in advanced manufacturing and materials science. TECHNICAL SUMMARY This research investigates new strategies for synthesizing bulk nanotwinned metals – materials that combine high strength, ductility, and electrical conductivity through nanoscale twin boundaries. These interfaces enhance mechanical performance, thermal stability, and damage tolerance, making them desirable for extreme structural applications. Despite their promise, nanotwinned metals remain limited to thin films and small-scale components due to challenges in controlling twin formation during bulk processing. This project is establishing a fundamental understanding of how to intentionally and scalably produce prolific deformation twins in bulk metals and alloys. The central hypothesis is that suppressing competing microstructural mechanisms – such as dislocation cell formation in laser powder bed fusion (L-PBF) and recrystallization in additive friction stir deposition (AFSD) – can promote deformation twinning across large volumes of material. Specifically, thermal fatigue from rapid heating and cooling in L-PBF and intense shear deformation in AFSD offer unexplored but promising pathways for twin formation. To evaluate this hypothesis, the project develops and applies two cryogenically modified additive manufacturing techniques: (1) cryogenic L-PBF, where sub-ambient cooling increases solidification rates to disrupt dislocation substructures; and (2) cryogenic AFSD, a novel extension of solid-state processing that couples high strain rates with thermal control to limit recrystallization and enhance twinning. Low- and medium-stacking-fault energy metals, including Cu and Cu-Al alloys, serve as model systems for this investigation. A systematic experimental approach employs electron microscopy and nanoindentation to elucidate how processing conditions affect twin formation and local mechanical behavior. This early-stage work is establishing science-based protocols for engineering twinned structures in bulk form factors, seeking to expand their applicability beyond small-scale uses. In alignment with the EArly-concept Grants for Exploratory Research (EAGER) program, this project explores a high-risk, high-reward strategy while training a technically skilled workforce in advanced manufacturing and materials science. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.