Fabrication of a lightweight Al alloy mirror through 3D printing and replication methods

In order to realize rapid fabrication of a lightweight mirror, an AlSi10Mg alloy mirror was made through 3D printing and replication methods. The mechanical, thermal, and physical properties, the surface accuracy, and the dimensional stability were investigated. Through a selective laser melting method, an Al alloy mirror was printed and exhibited a low areal density of 28.4  kg/m². Through replication, the mirror surface accuracy was improved to 0.033λ (root mean square, λ=632.8  nm); surface roughness was 1.3 nm (Ra). The stability test result indicated that the 3D printed mirror presented good dimensional stability in air for a long time and in a temperature changing environment.