Microstructure and mechanical properties of Mg-4Zn-xGd (x=0, 0.5, 1, 2) alloys

The present work mainly focuses on the effect of minor content of Gd element on the microstructure and mechanical properties of Mg-Zn alloy. The Mg-4Zn-xGd (x=0, 0.5, 1, 2) alloys were fabricated and subjected to extrusion at 280 degrees C with the ratio of 25:1. Results revealed that the addition of Gd could inhibit the dynamic recrystallization (DRX) of Mg-4Zn alloy, and both the size and volume fraction of DRXed grains demonstrated a decreasing tendency as the Gd content increased from 0.5 to 2 wt.%. It is the weakening effect on DRX behavior that lead to the smaller amount of fine precipitate and the stronger texture intensity. As compared with the Mg-4Zn alloy, the yield strength and ultimate tensile strength of Mg-4Zn-xGd alloys were improved obviously by the addition of minor content of Gd, however, at the expense of elongation. Excellent tensile properties with the yield strength of similar to 369.8 MPa and ultimate tensile strength of similar to 400.3 MPa were obtained when the Gd content was 2 wt.%. (C) 2020 Published by Elsevier B.V. on behalf of Chongqing University.