Towards better understanding supersonic impact-bonding behavior of cold sprayed 6061-T6 aluminum alloy based on a high-accuracy material model

Abstract

Supersonic impact deformation-induced bonding is at the heart of the cold spray (CS) process, and therein lies the difficulty of clearly understanding CS behaviors. In this study, the supersonic impact-bonding behavior was systematically investigated by accurately reproducing the CS process using a newly developed material model (Ma-Wang material model) with 6061-T6 aluminum alloy (Al6061-T6) as the target material. First, the material properties of the Ma-Wang material model were identified using general flow stress data. Then, the high-fidelity modeling was fully confirmed by comparing the simulated and experimental coefficients of restitution and microparticle deformations over a wide range of impact velocities. More importantly, the rebound origin and bonding features of supersonic impacts between identical and dissimilar materials (Al6061-T6/Al6061-T6 and Al6061-T6/sapphire) were thoroughly explored, revealing that regardless of the substrate type, metallic plastic deformation is the main pathway for energy dissipation (dissipating approximately 90% of the energy). In addition, the rebound of metallic microparticles is highly dependent on the elastic recovery of the substrate. The difference is that during the supersonic impact between dissimilar materials, interfacial friction can be another important pathway for energy dissipation (dissipating approximately 10% of the energy). The coordinated deformation between microparticles and substrate favors supersonic impact-bonding. Further, the distinct features due to jetting and energy can be regarded as precursors to CS bonding.