Microscale additively manufactured 3D metal-ceramic nanocomposites with improved strength and thermal stability

Abstract

Nanocomposites hold great promise for enhancing material properties beyond those of conventional materials. Here, we present a novel method integrating template-assisted electrodeposition of nanocrystalline gold (nc Au) and atomic layer deposition (ALD) of alumina to fabricate three-dimensional nanostructured metal matrix composites (MMCs) with enhanced mechanical strength, reduced density, and improved thermal stability. Microcompression experiments demonstrate that Au-alumina MMC achieves a yield strength of 838 MPa, outperforming pure nc Au (792 MPa) and Au hollow microlattices (250 MPa). The strength advantage increases at elevated temperatures: the MMC exhibits a 5 % improvement in yield strength at room temperature while retaining only 80 % of the weight, rising to a 42 % improvement at 100 °C. To enable design and optimization of such nanocomposites, we performed a systematic thermomechanical study on pure nc Au. Compression tests across a range of temperatures (23 °C to 100 °C) and strain rates (0.0004 s⁻¹ to 216 s⁻¹) revealed a transition in deformation behavior around 1 s⁻¹ . In the quasistatic regime, strain rate sensitivity increased from 0.025 to 0.063 with temperature, while remaining low (0.013) and temperature-independent at higher strain rates. The increase in activation volume (10 b³ to 24 b³) and activation energy (49–83 kJ/mol) with strain rate suggests a change in the rate-controlling mechanism. These results provide essential input for finite element modeling (FEM) of MMC, enabling identification of architectural parameters that can be tuned to optimize strength before fabrication. This work demonstrates the potential of microscale additive manufacturing and hybrid fabrication strategies to produce nanocomposites with tunable thermomechanical properties for demanding structural applications.