Arresting the grain growth of nano grains in Copper for effective heat evacuation applications

Copper has been well known for its ability to conduct heat and/or electricity and is equally appreciated in automobile as well as electronic industries. However, at higher temperatures copper suffers from grain growth and hence subsequent decrease in thermal conductivity. Hence, stabilization of the microstructure becomes an important issue especially since copper finds applications in brake pads as heat evacuators. Friction Stir Processing (FSP) is a solid state processing technique which is effective in producing severely deformed microstructures and is capable of mixing/welding/processing nearly any combination of materials. FSP has been adapted to process copper with Yttria particles to obtain nanosized Yttria particles uniformly distributed in copper. Yttria being stable up to 1400oC, it is expected to anchor the grain boundary migration of the copper at medium to high temperatures. Grain size evolution as a function of the number of passes is studied with a simulative heat treatment that raises the samples temperature to 200oC and subsequently quenches it . Thermal conductivity will be correlated to the microstructure.