Quantitative 3D FIB-SEM Characterization of Single Cu Particle Impacts for Cold Spray Applications

Cold spray is a solid-state additive manufacturing process that produces coatings and standalone parts by accelerating micron-sized metallic particles to supersonic velocities. Upon impact, the particles and substrate undergo plastic deformation, surface oxide layers are disrupted, and direct metal-on-metal contact is achieved to attain metallurgical bonding. We use Laser-Induced Particle Impact Testing (LIPIT) to produce single microparticle impacts under carefully controlled conditions, enabling a unit-process understanding of cold spray physics. We analyze impact sites using focused ion beam–scanning electron microscopy (FIB-SEM) to quantitatively study bonding at particle-substrate and particle-particle interfaces, deformation at high strain rates, and microstructural evolution. This 3D mapping of bonded area informs processing parameter optimization and reveals limiting conditions for development of recrystallization.