A PCB with its base material as metal for the portion of the board that spreads heat is known as a MCPCB, which is another name for thermal or metal-backed PCs. One of the PCBs' sides is covered by this thick metal, which is typically copper or aluminum. Whether the metal is in the center, middle, or on the back of the mcpcb board, this metal core depends on where it is.
Aluminum, copper, or a combination of various special alloys could make up the metal core of the thermal PCB. The most popular type of aluminum is known as aluminum core PCB
link:http://www.bsinterconn.net