Friction stir welding of Al-Mg-Li 1424 alloy

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. (C) 2016 Elsevier Ltd. All rights reserved.