Molecular dynamics simulation of ultrasonic metal welding of aluminum alloys

Abstract

In this study, molecular dynamics simulation of the ultrasonic welding of aluminum alloys is presented. Ultrasonic metal welding is counted as a solid state consolidation of the mating parts, in which the growing interface temperature is far below the melting point of the material and the energy consumption is relatively low compared to the common welding processes such as arc welding. The reciprocating motion of the sonotrode on the mating parts combined with the application of external pressure in the process of ultrasonic welding is the source of temperature rise and strong plastic deformations at the mating interface. This contribution is devoted to study the interactive effect of the process parameters on the interface temperature, deformation process of the mating parts and the diffusion behavior of the interface atoms.

Molecular dynamics simulation of interface atomic diffusion in ultrasonic metal welding

“…This phenomenon may result from the repulsive forces between atoms of the same type at the interface, which prevent the diffusion of Al atoms from one crystal to the other. Further increase of the compression rate v does not show a significant decrease or increase in the diffusion coefficient, which is in good agreement with the results from Mostafavi and Markert [36].…”

Polymer–Metal Interfacial Friction Characteristics under Ultrasonic Plasticizing Conditions: A United-Atom Molecular Dynamics Study

“…The rationality of the model was verified by the interface displacement and temperature rise change, and it was also used as the initial condition of the friction model. Due to the temporal and spatial differences between the micro-nanoscale and macro-scale, the settings of physical parameters (such as velocity, frequency) will be much higher, even in orders of magnitude [ 50 , 51 , 52 ]. Therefore, the speed along the (0, 1, 0) direction under the SSF mode was set to 10 m/s, 15 m/s, and 20 m/s.…”

Nonuniform-to-uniform structural transitions induced by ultrasonic vibrations

“…On the atomic scale, molecular dynamics (MD) simulations have exerted attention on the atomic and strain-energy distributions at Al/Al, Cu/Al, Cu/Cu and Ti/Al interfaces joined via an UV-assisted method, 27–35 giving insights into the effect of UVs on the structural evolution of joints. However, there are still no direct images capturing atomic-scale motions of dislocations which, together with atomic diffusion, are involved and essential in material flow and plastic deformation in Mg/Al UVeFSW processes.…”

“…Computer simulations can therefore be an effective tool for probing relative problems. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] Wu's group [20][21][22][23][24] employed the computational fluid dynamics method and proposed novel constitutive models to investigate the action of UVs on material flow. Their models are based on the Eulerian formulation where materials are treated as non-Newtonian fluids with high viscosity, together with the consideration of the acoustic softening effect.…”

“…However, their numerical investigations focused on the dynamic processes occurring at a large scale (a few millimeters), and lack of motion profiles of dislocations on an atomic scale, even though their measurement of flow stress consists of the plastic-deformation term which is established based on the motions of dislocations. 25,26 On the atomic scale, molecular dynamics (MD) simulations have exerted attention on the atomic and strain-energy distributions at Al/Al, Cu/Al, Cu/Cu and Ti/Al interfaces joined via an UV-assisted method, [27][28][29][30][31][32][33][34][35] giving insights into the effect of UVs on the structural evolution of joints. However, there are still no direct images capturing atomic-scale motions of dislocations which, together with atomic diffusion, are involved and essential in material flow and plastic deformation in Mg/ Al UVeFSW processes.…”