High Heating Rate Sintering of Copper-Chromium Core-Shell Powders Prepared by Physical Vapor Deposition

Sintering of copper alloys by modern advanced manufacturing techniques often leads to thermal gradients causing abnormal grain growth and structural anisotropy. An approach to control the microstructure and properties of copper-chromium alloys sintered by conventional and high heating rate processes is presented. Our chromium coatings deposited onto copper particles using an in-house high-power impulse magnetron sputtering to produce core-shells as feedstocks for sintering processes demonstrated the ability to prepare alloys with tailored composition, microstructure, and mechanical and electrical properties. Due to the low solubility of chromium in copper, the Cr-Cu interface is responsible for pinning the grain growth. The Cu grains grow within the cores until they are stopped by the solute Cr phase, acting as segregates at the grain boundary and exerting a pinning force stabilizing the microstructure. When used as building blocks, core-shells can enable the advanced manufacturing of alloys with unique compositions, microstructures, and properties.