Dalong Zhang¹, Lin Jiang², Xin Wang³, Irene J Beyerlein⁴, Andrew M Minor⁵, Julie M Schoenung³, Subhash Mahajan⁶, Enrique J Lavernia³; ¹Pacific Northwest National Laboratory, ²Thermo Fisher Scientific, ³University of California, Irvine, ⁴University of California, Santa Barbara, ⁵University of California, Berkeley; Lawrence Berkeley National Laboratory, ⁶University of California, Davis

Mg-Y alloy with super-saturated solid solution was fabricated at EJL Lab using far-from-equilibrium processes, including gas atomization, hot isostatic pressing, and extrusion. Atom probe tomography (APT) revealed that the resultant alloy contained 1.6 at.% Y solid solution. The Mg-Y alloy exhibited a yield “symmetry”, in that the compressive yield stress (CYS) was nearly the same as the tensile yield stress (TYS), an uncommon and exceptional property compared to other Mg alloys. Post-mortem characterization revealed active prismatic slip and a “lack” of {10-12} deformation twins. In-situ TEM deformation on Mg-Y nano-pillars quantified the critical stresses for basal, prismatic, and pyramidal slip, confirming the multi-faceted effects of Y solid solution in enhancing non-basal slip, reducing intrinsic anisotropy in Mg, and impeding twinning. Far-from-equilibrium in-situ TEM study on pure Mg will also be discussed briefly, unveiling the peculiar behavior of pyramidal dislocation in the absence of Y.