Microstructure characterization and mechanical properties of gas tungsten arc welded cast A356 alloy

The microstructure and mechanical properties of the gas tungsten arc welded cast A356 alloy were investigated with fillers ER1100, ER4043, ER4047 and ER5356 under the pulse frequencies of 1, 3 and 5 Hz. Results showed that the filler metal and pulse frequency affected the grain structure of fusion zone considerably. The highest fraction of eutectic (44%) was formed with filler ER4047. Tensile fracture of all specimens indicated that fracture did not occur in the fusion zone. The greatest impact toughness (about 4 J) was achieved for the welds with filler ER4047 while the largest hardness (HV 90) was obtained with filler ER5356.