Molecular dynamics investigation of temperature effect and surface configurations on multiple impacts plastic deformation in a palladium- copper composite metal membrane (CMM): A cold gas dynamic spray (CGDS) process

ST Oyinbo and TC Jen, COMPUTATIONAL MATERIALS SCIENCE, 185, 109968 (2020).

DOI: 10.1016/j.commatsci.2020.109968

In clarifying the bonding mechanism and in the in-depth study of the property of coating in cold gas dynamic spray (CGDS), the analysis of multiple impacts techniques is of great importance. The development of atomic-scale structures and Microscopic analysis of the deformation mechanisms have proven to be of many advantages to molecular dynamic simulations. Thus, simulations of molecular dynamics (MD) are performed to determine the effect of temperature and surface configurations on multiple impacts plastic deformation in Pd-Cu composite metal membrane (CMM) interfaces during CGDS. The results suggest that the analysis of temperature and plastic strain at different preheating temperatures showed an understanding of multiple impact behaviour. The interfacial layer thickness increases with temperature. Therefore, Pd-Cu cohesion occurs without melting at the interfacial zone. The interfacial bonding strength during this process emerged to be considerably higher at a higher temperature than that achieved during low temperature because the hydrodynamic behaviour between bonded atoms resulted from the elevated shear strain rate, shear plastic deformation and local fusion (thermal effect) at the interface of the contact region. The surface configurations of the substrate material also shown to have a significant impact on the process of deposition and deformation of the impacting clusters. As the temperature increases, the bonding process involves substantial plastic deformation at the interface, leading to the removal of interstices and total interaction between the contact pair. The Pd-Cu CMM interface obtained in this analysis has very good mechanical characteristics of approximately (0.70, 0.87, 0.96 and 1.06) GPa tensile strength at (300, 450, 550 and 650) K showing a tensile strength that is approximately similar with those from experiments.

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