Deformation-Induced Dynamic Precipitation and Resulting Microstructure in a Mg–Zn–Ca Alloy
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The microstructure of an Mg–Zn–Ca extrusion was investigated by transmission electron microscopy, and the interaction between dynamic precipitation and dynamic recrystallization was analyzed. The results showed that dynamic precipitation significantly affected the microstructure of the as-extruded Mg–Zn–Ca alloy. The pinning effects of precipitates on dislocations effectively prohibited dynamic recrystallization processes, while the grain boundary precipitate Ca2Mg6Zn3, inhibited the growth of dynamically recrystallized grains. Consequently, a bimodal microstructure with fine dynamically recrystallized (DRXed) grains and elongated deformed regions was obtained for the Mg–Zn–Ca extrusion. High-resolution transmission electron microscopy indicated that the intragranular precipitate MgZn2 had a crystal orientation relationship with α-Mg in the form of (0002)Mg//(10–13)MgZn2 and [1–100]Mg//[1–210]MgZn2, which was beneficial for strength improvement.
The authors are grateful for the financial support from Shaanxi Provincial Department of Education Fund (No. 17JK0538).