Investigation of the Effect of Cerium on the Structure and Properties of Calcium-Containing Aluminum Alloys

A new Al–Ca–Ce alloy system is investigated which is the basis for creating “natural composites” based upon aluminum. With the help of thermodynamic calculations and experimental studies of alloy structure and phase composition for all of the structure and elements of the composition diagram for an area rich in aluminum is proposed: projection of the liquidus surface and phase distribution in the solid state. The composition and structure of primary crystals of the phases Al₄Ca and Al₁₁Ce₃ in equilibrium with an aluminum solid solution are studied using the XMRA and XPA methods, and mutual solubility of calcium and cerium within these phases is established with formation of compounds Al₄(Ca,Ce) and Al₁₁(Ce,Ca)₃. Changes in primary crystal and eutectic microhardness as a result of calcium and cerium mutual solubility within them are investigated. Using nonequilibrium crystallization calculated data according to the Scheil–Gulliver model, in particular direct and differential thermal analyses, alloy critical temperatures and L → [(Al) + Al₄Ca + Al₁₁Ce₃(Al₄Ce)] ternary eutectic reaction temperature are calculated. Prospects for eutectic alloy Al6.5Ca3.5Ce as a high-tech heat-resistant “natural composite” are demonstrated.