Transmission Electron Microscopy Study of Microstructure Evolution of Al-Mg-Sc Alloy after Annealing at 120°

M. Šlapákováa, B. Křivskáa, J. Bajera, O. Grydinb, M. Stolbchenkob, M. Cieslara aCharles University, Faculty of Mathematics and Physics, Department of Physics of Materials, Ke Karlovu 5, 121 16 Prague 2, Czech Republic bUniversity Paderborn, Faculty of Mechanical Engineering, Lehrstuhl für Werkstoffkunde Microscopy, Pohlweg 47-49, 33098 Paderborn, Germany

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The Al-Mg-Sc alloys are used in aerospace and ship-building industry due to their good mechanical properties such as corrosion resistance, weldability and possibility for superplastic forming. Addition of Sc with Zr may further lead to enhancement of their performance by precipitation of coherent particles of Al3(Sc,Zr) phase which are known to stabilize the microstructure and hinder the recrystallization. The role of the material processing on the microstructure and mechanical properties evolution was studied by means of transmission electron microscopy, scanning electron microscopy and resistivity measurement. The Al-Mg-Sc-Zr alloy was manufactured by two different manners - conventional casting and twin-roll casting and subjected to deformation by equal-channel angular pressing. The shape and nature of the grains significantly influenced precipitation of β-phase Al3Mg2, which may be detrimental for such kind of materials in the terms of corrosion resistance. The worst properties exhibited the conventionally cast and rolled material with a pancake grain structure where the β-phase particles forms as continuous layer along the (sub)grain boundaries.

DOI:10.12693/APhysPolA.134.871 PACS numbers: 81.05.Bx, 81.40.Cd, 81.40.Ef, 81.40.Rs, 61.72.Ff