Oh yeah, they're carbide! ("Solid micrograin carbide", not coated).
The graph above was posted by a Frenchman (Roscal?) and shows the heat dissipation pattern through a typical "maze" block. I really don't remember any other details about it, unfortunately. Either way, the point was that the heat spreads radially from the shape of origin.
I recently came across a term called "cold casting", which has the advantage of not putting any air (or oxygen) in the copper. I haven' pursued it more than that. Surely it's casting at a relatively high temperature, but probably not as high as one might expect. On the other hand, maybe its more akin to filling the mold with copper bits, then gently melting it into shape... I really dunno.
|