Friction stir welding of Al–Mg–Li 1424 alloy

• Friction stir welding of ultra-light (density = 2.54 g/cm3) Al-Mg-Li 1424 alloy resulted in high joint efficiency of 97%.
• Contrary to 2XXX and 7XXX alloys, no knockdown in strength in heat affected zone after post weld heat treatment was observed.
• Homogeneous, fine, and dense precipitation of Al3Li precipitate led to full recovery of strength.

Friction stir welding of 1424 Al–Mg–Li alloy was conducted using tool rotation rate of 800 rpm and traverse speed of 305 mm per minute. Two welds with different thermal conditions were made by using external cooling mediums. The temperature at the tool center was recorded for each weld. After post weld heat treatment, full recovery of strength was observed in the heat affect zone and the weld nugget. High joint efficiency of 97% of the base material was achieved. Transmission electron microscopy and differential scanning calorimetry studies were performed for microstructural evaluation. Homogenous and high density of Al3Li precipitation was reasoned for high strength joints.

Figure optionsDownload as PowerPoint slide