  The influence of Fe content on the three-dimensional (3D) morphology of
Fe-rich intermetallic phases (Fe phases), Al2Cu, and pores and mechanical
properties of cast Al-5.0Cu-0.6Mn alloys with 0.5 and 1.0 wt. % Fe are
characterized using synchrotron X-ray tomography and a tensile test. The
results show that both Fe phases and Al2Cu exhibit a complex 3D network
structure, and the pores are irregular with complex interconnected and
near-globular shape. As the Fe content increases from 0.5 % to 1.0 %, the
volume fraction and equivalent diameter of Fe phases decrease, whereas both
their interconnectivities decrease. Skeletonization analysis shows that the
Chinese-script-shaped Fe phase is compacted than the plate-like Fe phases. The
equivalent diameter and sphericity of pores vary with Fe content, and their
relationships follow exponential functions, Y = 7.14*X-1.29 and Y =
7.06*X-1.20, respectively. The addition of Fe results in a decrease in the
ultimate tensile strength and elongation from 223.7 MPa to 199.8 MPa and from
5.51 % to 3.64 %, respectively, owing to increasing volume fraction of
sharp-edged Fe phases and pores, resulting in stress concentration during
tensile test.
