Traditionally, the thermal conductivity of aluminum casting alloys has been significantly lower than extruded alloys. This, coupled with the potential for air pockets and inclusions in some casting styles, can yield poor thermal designs. These materials offer conductivity close to extruded aluminum but still are limited by fin height to spacing ratios noted here. Many companies are working to develop these next generation products. Improving Thermal Conductivity Thermal conduction comes into play in two areas, heat spreading in the base, and fin efficiency.
Conduction is the transfer of heat within a material due to intimate contact between molecules.
To overcome this conduction limitation many alternative materials and techniques are being explored. Vapor chambers Each of these materials or systems will increase heat conduction compared to an aluminum extrusion. However, they will all be more costly and maybe heavier than aluminum. That's the good news. The down side of copper is that it weighs three times more than aluminum, costs the same on a per pound basis and is more difficult to machine.