Effect of Calcium Addition on the Aluminum Alloy A201 Foam

To study the effect of calcium on the porosity, sphericity, and microstructure of Al-Cu foams, a gradient calcium content (0.5, 1.0, 1.5, and 2.0 wt%) is added into aluminum A201 alloy (Al-Cu alloy) for the cellular aluminum foam preparation via the melt foaming method (TiH2 is used as a bubbling agent). Thereafter, the porosity of the prepared Al foams and their pore size are found to increase, and the sphericity of pores tends to approach to unit with calcium addition. This phenomenon is then explained through the modified thermophysical properties (i.e., surface tension and viscosity) of A201 alloy melts caused by the calcium addition. After the microstructure analysis, a bunch of secondary phases in the A201 + Ca alloy foams, e.g., CalAl(2)Si(2), Al2Cu, and Al20CaTi2 as well as an eutectic phase with a great copper content Al8CaCu4 are detected by means of scanning electron microscopy/energy-dispersive X-Ray spectroscopy and X-Ray diffraction analysis.