Solute atom mediated Hall-Petch relations for magnesium binary alloys

The solute atom mediated Hall-Petch relations for Mg-Y, Mg-Al, Mg-Gd and Mg-Zn alloys were reported at an equivalent nominal solute content of 0.35 at.%, namely, the obviously lower Hall-Petch slope k for Mg-Y (220 MPa mu m(1/2)) and Mg-Gd (285 MPa mu m(1/2)) than that for Mg-Al (324 MPa mu m(1/2)) and Mg-Zn (322 MPa mu m(1/2)) under compression along the extrusion direction (ED). The addition of Zn or Al forms a strong basal texture, which will lead to a [1012) twinning predominant deformation under compression along the extrusion direction (ED). In contrast, the addition of Gd or Y develops a weakened texture, and thus both {10 (1) over bar2} twinning and basal slip are extensively activated. The lower k for basal slip and the favorable effect on activating {10 (1) over bar2} twinning by the basal slip result in a lower k in Mg-Y and Mg-Gd. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

The solute atom mediated Hall-Petch relations were investigated for Mg-Y, Mg-Al, Mg-Gd, and Mg-Zn alloys at a nominal solute content of 0.35 at.%. It was found that Mg-Y and Mg-Gd exhibited significantly lower Hall-Petch slope (k) values (220 MPa·μm(1/2) and 285 MPa·μm(1/2), respectively) compared to Mg-Al and Mg-Zn (324 MPa·μm(1/2) and 322 MPa·μm(1/2), respectively) under compression along the extrusion direction. The addition of Zn or Al led to a strong basal texture and predominantly basal slip deformation, while the addition of Gd or Y resulted in a weakened texture and activation of both {10 (1) over bar2} twinning and basal slip. This difference in deformation mechanisms contributed to the lower k values in Mg-Y and Mg-Gd alloys.