Abstract
? 2022 Elsevier B.V.Microstructural evolution and mechanical properties of a Mg?8Zn?6Al?1Gd (wt%) alloy were thoroughly investigated in this work. The results indicate that the dominant intermetallic phases in the as-cast sample are ?-Al2Mg5Zn2, τ-Mg32(Al,Zn)49, i-Mg44Al15Zn41 and Al2Gd phases and almost free Gd was detected in the former three phases. After extrusion, the sample has a fully recrystallized microstructure with the average grain size being ~1.5 μm, and exhibits a weak rare earth texture. Additionally, fine particles were approximately homogeneously dispersed in the fine-grained structure. Most of them are quasicrystal phase (i-phase) but have no identical orientation relationship with Mg matrix regardless of whether they distribute at grain boundaries or inside grains. Finally, the as-extruded sample exhibits good strength-ductility balance in both tension and compression and simultaneously has a slight reverse tension/compression asymmetry. Microstructural observations indicate that the excellent mechanical performance of the studied alloy is highly related to its fine grains, weak RE texture, and numerous homogeneously distributed fine particles.
NSTL
Elsevier