The authors report measurements of the thermal conductivity, specific heat, and critical temperature of the aluminium alloy 5056 in the range 0.05 to 1.3K. The absence of magnetic anomalies in the specific heat and the rather high thermal conductivity in the superconducting state would allow reasonably fast cool-down below 0.1K of multiton gravitational wave antennae made of this material. On the basis of the measured properties, the desired refrigerator characteristics are discussed.