Effects of solidification rate, Fe, and Ca on the cast microstructure of aluminum alloy A356

The effects of solidification rate, Fe, and Ca on the characteristics of the constituent phases formed during solidification of aluminum alloy A356 have been investigated. This involved the use of unidirectionally cooled laboratory-size ingots with a range of solidification rate of 0.2-7.5 K/s. Two levels of Fe (0.05 wt.% and 0.20 wt.%) and Ca (0 ppm and 59 ppm) were investigated. Both average dendrite cell and constituent phase particle size decreased exponentially with increase in solidification rate. At the levels investigated, Ca and Fe did not have any statistically significant effect on the volume fractions and characteristics of the constituent phases.