Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5458287 | Journal of Alloys and Compounds | 2017 | 11 Pages |
Abstract
An as-extruded Mg-11.5Gd-4.5Y-1.5Zn-0.4Zr (wt %) alloy with an excellent strength-ductility balance has been successfully developed by pre-annealing and hot extrusion. The effects of pre-annealing on microstructure and mechanical properties have been studied. Results show that the Mg5RE (RE: rare earth) particles, which are generated by pre-annealing treatments, are cracked during hot extrusion, and resulting Mg5RE fragments not only enhance the recrystallization of particle simulated nucleation (PSN), but also improve the continuous dynamic recrystallization (C-DRX) by promoting the grain subdivision. After hot extrusion, the studied alloy exhibits a bimodal microstructure consisting of fine DRXed grains with relatively random orientations and coarse un-DRXed grains with strong basal texture. Increasing the pre-annealing duration raises both the quantity of Mg5RE particles and the fraction of DRX, thereby decreasing the strength but increasing the ductility. With pre-annealing for 1 h the studied alloy achieves the best strength-ductility balance with tensile yield strength (TYS) of 377 ± 1.2 MPa and elongation to failure (EL) of 10.8 ± 2.0%. Further pre-annealing degrades the ductility due to the excessive Mg5RE particles. The alloy strengthening is attributed to the bimodal microstructure, Mg5RE and long-period stacking ordered (LPSO) phases, solute segregated SFs, and texture.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Zijian Yu, Chao Xu, Jian Meng, Xuhu Zhang, Shigeharu Kamado,