The figure below shows the morphology of primary austenite of cast iron prepared under different vibration frequencies. Figures (a) – (d) show the morphology of primary austenite of cast iron prepared at vibration frequencies of 0, 35, 50 and 100Hz respectively.
It can be seen from the figure that in the EPC cast iron without vibration, the content of austenite is high, and the primary dendrite and secondary dendrite are relatively developed. When the vibration of 35Hz is applied to the lost foam casting of cast iron, the primary austenite has more developed primary dendrite arm, and the secondary dendrite is not developed; When the vibration frequency increases to 50Hz, the primary dendrite arms in the cast iron alloy are less, and the primary austenite is equiaxed.
When the vibration frequency increases, the change of primary austenite morphology in the alloy is mainly due to the combined action of motion resistance and inertia force on austenite dendrites during solidification, and the action mechanism is shown in the discussion section.