Influencing the Powder Particle Incorporation in High‐Speed Laser Melt Injection

Metal–matrix composite (MMC) layers can be used for increasing the wear resistance and for applying specific textures on tools such as skin‐pass rolls and pressure die‐casting pistons. For producing such MMC layers with high productivity, high‐speed laser melt injection is developed. Since high laser intensities are required for reaching high process speeds, strong laser–powder interactions can occur resulting in undesired deformations and agglomerations of powder particles. Interactions can occur both during the particle transport from the nozzle to the melt pool and during the particle incorporation in the melt pool. This article focuses on the incorporation behavior of spherical fused tungsten carbide (SFTC) particles in the tool steel 1.2362. First, a simplified model is built in order to determine the factors affecting the incorporation. Second, the incorporation of SFTC particles is analyzed by high‐speed imaging. It is found that the kinetic energy of the particles at the beginning of the incorporation has a decisive influence on the incorporation time. Whereas most particles are incorporated directly, 10% to 40% of the observed particles float on the melt pool surface before being incorporated.