Scattering signatures of dynamic precipitation and plasmonic response in Mg-2Zn-2Gd alloy

Magnesium (Mg) alloys have important structural and functional applications. The primary objective of this project is to elucidate the mechanisms governing the exceptional combination of high strength and ductility in Mg alloys with zinc (Zn) and gadolinium (Gd) under severe plastic deformation by multi-axial forging (MAF). Emphasis is placed on the process-structure-property relationship understanding of dynamic precipitation occurring during MAF. We employ small-angle X-ray scattering (SAXS) to detect and characterize nanoscale precipitates. By modeling with the combination of spherical form factor and Guinier principles, grounded in experimental and theoretical scattering, SAXS enables us to determine size distributions, number density and impact of processing by 1-MAF pass and 2-MAF passes. This approach provides critical insight into the role of nanoscale precipitation in tailoring microstructures and mechanical response of the alloy due to severe plastic deformation. Importantly, the observed precipitate dimensions in Mg alloys can support local surface plasmon resonance (LSPR) which leads to inexpensive and stable nanoparticle plasmonics spanning the entire UV-vis-NIR spectral region. The connection between structural evolution, SAXS and SEM characterization, and potential plasmonic activity suggests multifunctional applications for precipitation containing Mg alloys, tailoring both mechanical and optical properties.