The effect of aluminum (0, 2, 4, and 6 wt. %) and copper (0, 2, 4, and 6 wt.
%) are investigated on graphite morphology, microstructure and compressive
behavior of ductile iron specimens manufactured by sand casting technique.
The graphite morphology and microstructure are evaluated using optical
microscopy (OM) and scanning electron microscopy (SEM) equipped image
processing software. To study the mechanical properties, the compression
test is conducted on the ductile iron specimens. The results indicate the
surface fraction and nodule count of graphite decrease by increasing the
amount of aluminum from 0 to 2 wt. % and then, increasing from 2 to 6 wt. %.
In addition, the nodularity of graphite increases by the increment of the
aluminum amounts. By adding the amount of copper, the surface fraction and
nodule count of graphite increase and nodularity of graphite decreases. The
addition of aluminum and copper decreases the surface fraction of ferrite
and increases the surface fraction of pearlite in the microstructure. By
increasing the amounts of aluminum and copper, compressive stress vs. strain
curves are shifted upwards, and modulus of elasticity, yield strength,
maximum compressive stress and fracture strain improve. In comparison with
copper, aluminum has a greater influence on the mechanical properties of
ductile iron.