Solute atom mediated Hall-Petch relations for magnesium binary alloys

Abstract

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 μm1/2) and Mg-Gd (285 MPa μm1/2) than that for Mg-Al (324 MPa μm1/2) and Mg-Zn (322 MPa μm1/2) under compression along the extrusion direction (ED). The addition of Zn or Al forms a strong basal texture, which will lead to a {101¯2} 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 {101¯2} twinning and basal slip are extensively activated. The lower k for basal slip and the favorable effect on activating {101¯2} twinning by the basal slip result in a lower k in Mg-Y and Mg-Gd.