In this tutorial, the cold spray process is simulated using the SPH (Smoothed Particle Hydrodynamics) method in Abaqus.
Cold spray is a coating technique where powder particles, typically 10–40 µm in size, are accelerated to very high velocities (200–1200 m/s) by a supersonic compressed gas jet. Importantly, this occurs at temperatures below the melting point of the particles.
When the particles impact the substrate, they undergo extreme and rapid plastic deformation. This breaks up the thin oxide films present on the surface of metals and alloys. As a result, clean metal surfaces come into intimate contact under high local pressure, allowing bonding to occur. Thick layers of material can then be deposited quickly, with deposition efficiencies often above 90%.
Unlike thermal spray methods, which rely on heat to melt or soften the feedstock, cold spray avoids thermal degradation and oxidation of the coating material. Thermal spray also requires controlled atmospheres or vacuum conditions for oxidation-prone metals, increasing cost. Additionally, thermal spray introduces residual stresses into coatings, limiting achievable thickness and requiring careful thermal management to prevent substrate damage.
Cold spray, however, deposits material without high thermal loads. This produces coatings with low porosity and minimal oxygen content.
In the simulation, the SPH formulation with a dynamic explicit procedure is applied. Adjustments are made in the step definition to include thermal variables in the output, since SPH elements do not directly account for temperature. A high initial velocity is assigned to the particle. During impact, large plastic strains occur, while the temperature remains far below the melting point. This confirms the suitability of the cold spray process.
Figures of the assembled parts and simulation results are shown below.
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