Abstract

Cold gas dynamic spraying (CGDS), as a high strain rate shearing and innovative solid-state technique enables to rapidly develop additive manufacturing and coating for metal deposition. This paper investigates the development and evolution of various interfacial bonding characteristics during high strain rate shearing process through Multiphysics numerical simulations of single particle impact. Two different particle-based modeling strategies such as smoothed particle hydrodynamics (SPH), molecular dynamics (MD) are investigated using commercial software ABAQUS/Explicit and LAMMPS, respectively. To separate the difficulties related to complex metallurgy of alloys, our first investigations focus on pure aluminum. The Johnson-Cook (J-C) constitutive model is used to describe the high strain rate self-consolidation process in SPH modeling. Embedded Atom Method (EAM) is used to describe the interactions between Aluminum atoms in MD modeling. The predictions from the different particle-based models are compared with each other and with experimental results. Through the investigations, SPH numerical approach has strong advantage in capturing the phenomena that occur during the cold spray process. It is able to describe the complex features of particle and substrate, especially in the interface vicinity. At the same time, MD numerical approach gives the fundamental understanding of the deposition behavior at the atomistic level. The key finding is the strong relationship between the un-uniform distribution of shear strain and jet formation during high-speed collision. Plastic strain along with an increase of temperature lead to thermal softening of pure Aluminum resulting in metallurgical bonding at the interface.