After composition adjustment,
argon was purged into the melt through a stainless steel tube (6mm inside
diameter) with a zircon coating. This purge was performed to degas hydrogen. The
degassing timewas 3min in each experiment with a flow rate of 4 L/min at 0.2 MPa.
The experimental setup for fluidity testing is shown in Fig. 1. This experimental
setup has been used successfully in previous work [14]. The molten aluminum alloy
was poured into a mold made of CO2 silicate sand lined with a zircon coating. This
mold had been preheated to 400 ◦C with an electrical resistant furnace. The tip of
a K-Type thermocouple probe was set 10cm from the top of the mold to measure
the temperature of molten aluminum inside the mold. This position was adjacent
to the end of a quartz tube with 7mm ID, 9mm OD, and 650mm length. The end of
the quartz tube was inserted at the center of the mold, 10cm below the top of the mold, immediately after the mold was filled with molten aluminum.