Description

Joining copper and aluminum sheets is difficult because of brittle intermetallic phases (IMP) formed in the joint, which results in reduced performance. The traditional approach to overcome this issue is to irradiate the laser beam from Aluminum (Al) to control the weld depth and mixing of Cu in Al. The laser welding approach from the copper side (Cu on top) to Al is very sparse in the literature.

In this paper, the welding approach from copper (top sheet) to aluminum is studied with green laser (515 nm) due to improved absorption at this wavelength. The objective of irradiating the laser beam from the copper side (Cu on top) is to exploit the higher solubility of Al in Cu (about 18%), which is significantly higher than Cu in Al. Therefore more Cu and Al can be melted and mixed in the joint for copper sheet placed on the top. From the tensile shear test, a strong joint is obtained with a fracture on the heat-affected zone (HAZ) of Al. Detailed microstructure and composition of Al and Cu in the joint is performed by Energy-dispersive X-ray spectroscopy (EDS) to investigate the composition in the joint. The EDS analysis indicates that a large amount of beneficial Cu solid solution and Al-rich phases is formed in the joint. The detrimental phases are intermixed in between the ductile phase composition i.e Al-rich and Cu solid solution. Therefore the effect of detrimental intermetallic phases is mitigated by intermixing with large ductile phases. With this paper, the fusion welding approach for joining Cu and Al system with a significant level of Cu and Al melting is shown.

Contributing Authors

  • Karthik Mathivanan
    University of Luxembourg
  • Peter Plapper
    University of Luxembourg
Karthik Mathivanan
University of Luxembourg
Track: Laser Materials Microprocessing
Session: Micro Session IV
Day of Week: Tuesday
Date/Time:
Location:

Keywords

  • Copper-Aluminium Joints
  • Failure Analysis
  • Green Laser Welding
  • Intermetallic Phases