Fabrication of an athermal mirror from a hyper-eutectic AlSi alloy via LPBF

This study explores the use of a combination of the hypereutectic aluminum-silicon alloy AlSi40 and electroless nickel
(NiP) for optical mirrors in space-borne instruments. The combination of AlSi40 and NiP offers a solution to the trade-offs
between optical performance, structural integrity, manufacturing time and price that traditional materials used for optical
space applications have. AlSi40 is processable by additive technologies like Laser Powder Bed Fusion (LPBF), which allows
the design and fabrication of optical components with optimized internal structures (e.g. lattice structures) resulting in
increased stiffness-to-mass ratio of the component, which is crucial for space applications. The process chain, including
parameter development and material characterization, was conducted and a demonstrator mirror was printed and tested
under representative operational conditions. The study also includes the transfer process of the parameters and the
experimental conditions between several AM machines, to ensure the scalability and reproducibility of the process.