Effect of filler metal composition on the microstructure of Al-Li alloy (1441) welds

The influence of the filler metal composition on the microstructure of the weld bead in Al-Li alloy 1441 (Russian) was studied. The gas tungsten arc welding process was employed in this investigation. Filler metals used were: parent alloy 1441, AA 2319, AA4043, AA 5356 and AA 5556A. Weld metal dilution was found to be in the range of 65 to 75% in all cases. The grain structure was predominantly equiaxed, in contrast to the columnar structure reported earlier in autogenous welds. The composition of filler metal used was shown to influence (i) the extent of fine equiaxed zone near the fusion boundary, (ii) the grain size and (iii) the distribution of the interdendritic phase in the fusion zone.