This paper present the results of a diamond turning study of a rapidly solidified aluminium 6061 alloy grade, known as
RSA6061. It is shown that this small grain material can be diamond turned to smaller roughness values than standard
AA6061 aluminium grades. Also, the results are nearly as good as nickel plated surfaces, but the RSA6061 has the
advantage that no additional production steps are needed and that no bi-metallic bending or delamination can occur in a
thermally changing environment, e.g. when cooling to cryogenic temperature. Therefore, RSA6061 is a good material for
optical applications in the visual spectrum.