Synthesis of Nanostructured WC-Co Hardmetal by Selective Laser Melting

Abstract

Selective laser melting is a layer-by-layer technique to form a solid part from powder. The thermal cycle of this process can be as short as one millisecond and less. This is why it is favorable to obtain nanostructured materials with advanced properties. Metal matrix composite WC-Co is studied. Micron-sized Co powder was mixed with WC nanopowder in a planetary ball mill to prepare uniform composite powder. Single remelted beads and monolayers were obtained from the composite powder on the substrates of sintered WC-Co. No cracks and good adhesion to the substrate are observed. The high cooling rate up to 10⁶ K/s explains the fine microstructures. Increasing the scanning velocity is favourable because of refining the microstructure and decreasing the balling-effect. The attained values of surface roughness are as low as 1-2 μm.