Sandia Labs FY22 Laboratory Directed Research & Development Annual Report

FY22 ANNUAL REPORT

DESIGNING FUNCTIONALLY GRADED METALLIC COMPOSITES TO ENABLE INTERFACIAL PROPERTIES TAILORED TO MISSION-SPECIFIC NEEDS.

Functionally graded materials have properties that gradually change throughout the material body to enable tailorable responses to external stimuli. The goal of this project was to design tailored, multifunctional, metallic composites with materials properties far surpassing conventional technologies. Enabled by additive manufacturing, this work focused on maturation of near-net shape-processing capabilities targeting a multifunctional materials framework with highly tunable properties to establish a trajectory toward agile, materials-by-design solutions for a wide-range of Sandia and DOE mission-relevant applications. The team used laser-engineered net shaping with multiple powder hoppers to print functionally graded material with extraordinarily high hardness (~15 GPa) and

fracture toughness (~70-90 MPa-m1/2) in the transition region. These results were verified on single composition prints with multiple techniques, including nanoindentation and scratch testing. High-resolution microscopy and simulations revealed that plasticity is controlled through the creation of slip planes that are unable to cross phase boundaries. This three-year project has nine published journal articles including ones at Physical Review Letters , Journal of Materials Research , and Acta Materialia , with two others currently in preparation. The team collaborated with faculty at Johns Hopkins University, and Sandia Alliance partners University of Illinois at Urbana Champaign and University of Texas at Austin. (PI: Michael Chandross)

The structural and compositional analysis of an undeformed Ni59.5Nb40.5 alloy built on a Vitreloy 105 substrate using electron backscatter diffraction. Inverse pole figures and phase maps are shown for (A) the region near the substrate, (B) the middle region, and (C) the top region.

Sandia has spent decades developing new additive manufacturing tools and processes to fulfill its unique national security mission. Preview the latest advancements in multi-material AM available for licensing and partnerships. Visit ip.sandia.gov to learn more.

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