New Casting Alloys Based on the Al+Al 4 (Ca,La) Eutectic

The structure of the previously unstudied ternary Al-Ca-La system near the aluminum corner has been analyzed using experimental [scanning electron microscopy, electron microprobe analysis (EMPA), and x-ray diffraction analysis (XRD)] and computational analysis (thermodynamic calculations). Based on the experimental data, the projection of the liquidus surface and solid-state phase-field distribution of the ternary system have been suggested. It is shown that Al4(Ca,La) and Al11(La,Ca)3 compounds can be in equilibrium with aluminum. EMPA and XRD analyses have revealed significant mutual solubility between the binary Al4(Ca,La) and Al11(La,Ca)3 intermetallics which leads to significant changes in their structure and mechanical and physical properties. The analysis of hot tearing susceptibility together with linear contraction showed that new Al-(2–4)wt.%Ca-(0–2)wt.%La-1.5 wt.%Mn hypoeutectic quaternary alloys have excellent casting properties comparable to those of the most manufacturable casting branded aluminum alloys, e.g., A356 and 361.