Prediction of deformation characteristics and critical velocities during cold-spray: A new 3D model

So far, numerical models in the Eulerian frame have proven effective in investigating deformation behaviors and predicting critical velocities of cold sprayed deposits. Although the previously developed thin parallel-sliced model from the center of a particle could significantly reduce the calculation time under the satisfied calculation accuracy, the assumed model is associated with an infinitely long cylinder instead of a sphere, thus making the output unreal. In this study, a new slice model was developed. The newly established model can not only provide accurate predictions of deformation characteristics but also reduce computational cost to 14 % as compared to the 1/4 particle model. Key issues of deformation characteristics and critical velocities concern tuned preheated temperatures of Ni particle and Ni substrate over the varied particle sizes. If a Ni particle with a diameter of 20, 40 and 60 μm is used, similar deformation morphologies with different maximum PEEQ and temperatures are obtained. This is so because the mesh resolution proportionally scales with the particle size. In the cases of either of preheated particle and substrate, or both, the deformation of particle and substrate is accordingly increased due to the thermal softening. The requirements for obtaining a series of critical velocities in cold sprayed different materials are elucidated, in particular regarding Zn of 340 m/s, Cu of 380 m/s, Fe of 450 m/s, Ni of 470 m/s, Al of 550 m/s, Ti of 650 m/s and In718 of 660 m/s. The achieved knowledge could be also be transferred to cold spraying simulation of multiple particle impacts.