Spot impact welding of an age-hardening aluminum alloy: Process, structure and properties

• Published in: Journal of manufacturing processes Vol. 37; pp. 42 - 52
• Main Authors: Kapil, Angshuman, Lee, Taeseon, Vivek, Anupam, Cooper, Ronald, Hetrick, Elizabeth, Daehn, Glenn
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2019
• Subjects: Aluminum alloy; Heat treatment; Mechanical properties; Re-solidified molten zones; Vaporizing foil actuator welding; Weld interface; Mechanical properties; Heat treatment; Weld interface; Re-solidified molten zones; Vaporizing foil actuator welding; Aluminum alloy
• ISSN: 1526-6125; 2212-4616
• DOI: 10.1016/j.jmapro.2018.11.006

Naturally aged AA6111 was successfully spot-welded to itself using vaporizing foil actuator welding in as-received condition as well as after three different heat treatments. Material weldability, mechanical properties, hardness distribution, and weld interface characteristics were evaluated using lap-shear tests, micro/nanoindentation, optical and scanning electron microscopy and energy dispersive spectroscopy analysis. Lap-shear tests indicated that even after aging and varied heat treatments all samples had repeatable button pullout failure, the failure being governed by the thinning and tearing of the base metal around the weld nugget. The strength of the welds and the energy absorbed corresponding to the peak load varied with the heat treatments. Microhardness measurements displayed significant hardening in the weld regions compared to base metal hardness. Optical and scanning electron microscopy revealed re-solidified molten zones in the weld interface, and the extent and size of these zones varied with the heat treatments. Nanoindentation showed softening in these zones signifying presence of weld defects in the weld interior.