Formation of bonding interface in explosive welding-a molecular dynamics approach

Area of Science:

• Materials Science
• Computational Materials Science

Background:

• Explosive welding is a solid-state joining process used for dissimilar metals.
• Understanding the interface formation in copper-iron (Cu-Fe) bi-layer composites is crucial for advanced material applications.

Purpose of the Study:

• To investigate the atomic-level mechanisms of interface formation in Cu-Fe bi-layer composites produced by explosive welding.
• To analyze the influence of melting on the bonding interface structure and properties.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model the explosive welding process.
• The simulation included three sequential stages: loading, unloading, and cooling.
• Tensile tests were simulated at the atomic scale to evaluate interface strength.

Main Results:

• Three distinct types of bonding interfaces were identified, categorized by the occurrence of melting.
• The formation of nanograins near the interface was primarily attributed to melting and subsequent cooling.
• Atomic simulations demonstrated that melting is not a prerequisite for forming a stable bonding interface.

Conclusions:

• The joining mechanism in Cu-Fe bi-layer composites via explosive welding can be classified as pressure welding or fusion-diffusion welding, depending on whether melting occurs.
• MD simulations provide valuable insights into the complex phenomena governing interface evolution in explosively welded composites.