Decomposition Processes in the Anomalous Supersaturated Solid Solution of Binary and Ternary Aluminium Alloys Alloyed with Sc and Zr

Abstract

(X = Sc, Zr) particles. The loss of thermal stability of Al Sc alloys is due to the loss of coherence of the strengthening Al3Sc phase. In Al Zr alloys the loss of strength is due to the formation of a stable tetragonal DO23-ordered Al3Zr phase. After co-alloying of Al by Sc and Zr a bimodal grained structure was observed for the hypereutectic ternary alloy (Tquen. = 1400 • C). Nanosized grains of 50 60 nm were present on the boundaries of 1 2 µm large-sized grains. Transmission electron microscopy shows the formation of nanocomposite Al3Zr/Al3Sc particles. The formation of Al3Zr shell changes the nature of the interfacial t of the particle with the matrix and slows down the decomposition during the coalescence.

Effect of Sc:Zr Ratio on Superplastic Behavior of Ultrafine-grained Al-6%Mg-Sc-Zr Alloys

“…The composition of particles in Al-Sc-Zr alloys was studied in sufficient detail in many works (see, for example, [123][124][125][126][127][128][129][130][131][132][133][134][135]). As shown in [136], precipitation of Al3(Sc0.5Zr0.5) particles is more energetically favorable than that of Al3Sc and Al3Zr particles.…”