AL / CU Casting Alloy Match

[zigzag4]

Hi,

Can someone give me advice on a casting alloy of Al and / or CU that will have similar properties to 6063-T5 (an extruded alloy of aluminum)?

Key matches are:
Coefficient of thermal expansion
Thermal conductivity
Hardness

It also needs to be able to be machined easily and avoid cracking.

I've been recommended ADC12 but find that very wide of the mark.

Thanks