Effect of welding parameters on microstructure in the stir zone of FSW joints of aluminum die casting alloy

摘要

The effect of the welding speed and the rotation speed on the microstructure in the stir zone has been investigated by measuring the Si particle distribution in the ADC12 alloy. The stir zone has fine recrystallized grains without dendritic structures, and the eutectic Si was uniformly dispersed in the stir zone. The size of the Si particles was statistically determined in the stir zone using image processing. The number of finer Si particles, which is formed by stirring of the tool probe, increases during the FSW. Finer Si particles are distributed more in the bottom than in the other regions, though the size of the Si particles in the base metal is the same in all the regions. The size of the Si particles decreases with increasing welding speed. However, it is not significantly affected by the rotation speed.