Interface-governed nanometric machining behaviour of Cu/Ag bilayers using molecular dynamics simulation

Area of Science:

• Materials Science
• Mechanical Engineering
• Nanotechnology

Background:

• Investigating the mechanical and tribological properties of nanostructured materials is crucial for advanced manufacturing.
• Understanding subsurface damage mechanisms in nanometric machining is essential for precision engineering.

Purpose of the Study:

• To compare the nanometric machining behavior of Cu/Ag bilayers with pure Cu film.
• To analyze the influence of machining parameters on subsurface damage and material removal.
• To investigate the mechanical and tribological properties of Cu/Ag bilayers.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model the nanometric machining process.
• Analysis included dislocation movement, chipping volume, machining force, and workpiece temperature.
• Young's moduli were calculated using the Hertz contact mechanism.

Main Results:

• Cu/Ag bilayers showed lower hardness and higher friction coefficients compared to pure Cu film.
• Weaker metal bonding energy at the Cu/Ag interface contributed to reduced hardness.
• Increased indenter radius, tool speed, or machining depth led to higher forces, chipping volume, and temperature.
• Subsurface damage and lattice defects were minimized with smaller indenter radius, lower tool speed, and shallower machining depth.

Conclusions:

• The nanometric machining of Cu/Ag bilayers is influenced by interface bonding strength and processing parameters.
• Optimizing machining parameters (indenter radius, tool speed, machining depth) is critical for minimizing subsurface damage and enhancing surface quality.
• Lower tool speeds are particularly effective in improving the smoothness of the machined surface.