Abstract
Cold spray is an emergent sold-state manufacturing process based on high-speed consecutive collision of small sized particles powders. Such a cold process principle led to the recent development of coatings for various surface functionalization and direct component manufacturing applications. This study investigates the mechanisms of porosity formation during the additive growth of Al1050 powders. To this end, a thermo-mechanical computational model based on the Eulerian computational approach using the Johnson-Cook constitutive law is applied on the case of an additive growth from a stacking of powder layers. The model uses in-flight velocities measured by a DPV2000 system during a cold spray test and an isentropic gas flow model. The measurements show the velocity distribution within the powder jet at the nozzle exit and consists of a Gaussian-like distribution within the typical range of 450-650m/s. The centerline zone at the nozzle exhibits the highest velocity. These data used as input data of the model allowed to apprehend some circumstances of pore formation, in terms of site occurrence, pore behavior over time, and deficient in-flight velocity.
