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The rapid solidification of Al-30%Cu-18%Ag ternary alloy is investigated by using the free fall method. Its solidified microstructure is composed of θ(Al2Cu), α(Al) and ξ(Ag2Al) phases. The liquidus temperature and solidus temperature are determined as 778 and 827 K, respectively. The alloy melt undercooled amounts up to ΔTMax=171 K (0.20TL). Its microstructural evolution is investigated based on the theoretical analysis of undercooling behavior and nucleation mechanics. It is found that the undercooling increases with the decrease of the diameter of the alloy droplet. When ΔT<78 K, the primary θ (Al2Cu) phase of the alloy grows into coarse dendrite. When 78 K≤ΔT≤171 K, its refined θ (Al2Cu) phase grows alternatively with α(Al) phase. Once ΔT≥171 K, its microstructure is characterized by the anomalous (θ+α+ξ) ternary eutectic.
The rapid solidification of Al-30% Cu-18% Ag ternary alloy is investigated by using the free fall method. Its solid microstructure is composed of θ (Al2Cu), α (Al) and ξ Its microstructural evolution is investigated based on the theoretical analysis of undercooling behavior and nucleation mechanics. It is found that the solidus temperatures are determined as 778 and 827 K, respectively. The alloy melt undercooled amounts up to ΔTMax = 171 K (0.20 TL) When 78 K ≦ ΔT ≦ 171 K, its refined θ (Al 2 Cu) phase (Al 2 Cu) phase of the alloy grows into a coarse dendrite. Once ΔT≥171 K, its microstructure is characterized by the anomalous (θ + α + ξ) ternary eutectic.