Abstract Scope |
Cold-spray additive manufacturing (CSAM) is an emerging AM technology that can complete metallurgical bonding in solid-state through supersonic accelerated particle impact. It avoids melting-related issues such as solidification cracking, grain coarsening, and large thermal strain/stress. Nevertheless, the impact bonding of each micro-particle is finished within nanoseconds, which is impossible to be directly observed by experimental devices. The inevitable choice for CS-AM in-depth research is to reproduce dynamic phenomena by computational modeling. Using computational approaches, the first issue to be solved is to ensure that the established numerical model can accurately predict the supersonic impact behavior of particles, which is beyond the capabilities of most material models. In this study, a new material model considering extremely large strain, ultra-high strain rate, thermal softening, and dynamic recrystallization, named by Ma–Wang model or MW model, is developed. The accuracy of the MW model in predicting the large plastic deformation is validated by comparing it with the actual morphology of the deformed Cu micro-particle. The predicted grain size evolution by MW model is proved by comparing with the actual grain size distribution obtained by Electron Back-Scattered Diffraction (EBSD). On this basis, the impact behavior of a single Cu micro-particle is discussed in detail by combining numerical simulations and experimental validations, revealing the formation mechanism of extreme plastic deformation and its effect on the dynamic recrystallization and interfacial bonding. |