Microstructural and mechanical characterization of Al/Cu interface in a bimetallic composite produced by compound...

Area of Science:

• Materials Science
• Metallurgy
• Solidification Processing

Background:

• Aluminum-copper (Al/Cu) bimetals are crucial in various engineering applications.
• Achieving strong interfacial bonding in Al/Cu joints is challenging due to distinct material properties.
• Understanding diffusion bonding mechanisms is key to optimizing Al/Cu composite performance.

Purpose of the Study:

• To investigate the microstructure and shear strength of Al/Cu bimetals produced via compound casting.
• To determine the optimal casting parameters (temperature, solidification time, Cu wire diameter) for enhanced interfacial properties.
• To analyze the formation and impact of intermetallic compounds (IMCs) at the Al/Cu interface.

Main Methods:

• Compound casting of Al/Cu bimetals using varying Cu wire diameters (2.0-3.0 mm).
• Controlled variation of casting temperatures and solidification soaking times.
• Microstructural characterization of the Al/Cu interface using diffusion layer analysis.
• Shear strength measurement of the Al/Cu interface via punch testing.

Main Results:

• Intermetallic compounds (IMCs), such as CuAl2, were identified in the diffusion layer at the Al/Cu interface.
• Optimal casting at 680°C with a 15s solidification soaking time for a 3mm Cu wire maximized micro-hardness to 328 HV.
• Increased solidification soaking time led to thicker interface layers with lamellar eutectic microstructures, enhancing shear strength.

Conclusions:

• Casting parameters significantly influence the interfacial microstructure and mechanical properties of Al/Cu bimetals.
• The formation of IMCs and diffusion layer thickness are critical factors affecting hardness and shear strength.
• Optimized compound casting provides a viable method for producing high-strength Al/Cu bimetallic joints.