TY - JOUR

T1 - Elucidating the evolution of long-period stacking ordered phase and its effect on deformation behavior in as-cast Mg-6Gd-1Zn-0.6Zr alloy

AU - Lee, Sangwon

AU - Park, Yejun

AU - Go, Jongbin

AU - Kim, Young Mok

AU - Sohn, Seok Su

AU - LI, Jiehua

AU - Choi, Pyuck-Pa

PY - 2023/9/9

Y1 - 2023/9/9

N2 - Herein, the evolution of long-period stacking ordered (LPSO) phases in the as-cast Mg-6Gd-1Zn-0.6Zr (wt.%) alloy are investigated via transmission electron microscopy (TEM) and atom probe tomography (APT). The TEM results reveal that two types of LPSO phase (a bulky interdendritic phase and a plate-like matrix LPSO phase) are formed in the as-cast sample. Most of the LPSO phases are confirmed to be of the 14H type, with a smaller proportion being of the 18R LPSO. Further, the APT results reveal that the composition of the interdendritic LPSO phase is closer to that of the ideal 14H phase compared to the matrix LPSO phase, and both the interdendritic and matrix LPSO phases exhibit a Gd/Zn ratio of 2.5, thereby indicating a deficient Zn content compared to the ideal 14H phase (i.e., 1.3). In addition, the influence of the LPSO phases on the deformation behavior is investigated at different compressive plastic strains using electron backscatter diffraction (EBSD) analysis to reveal twinning and slip behavior during deformation. The results indicate that the LPSO phase induces additional work hardening in the late stage of deformation via the suppression of {101} compressive twinning and the activation of non-basal slip systems.

AB - Herein, the evolution of long-period stacking ordered (LPSO) phases in the as-cast Mg-6Gd-1Zn-0.6Zr (wt.%) alloy are investigated via transmission electron microscopy (TEM) and atom probe tomography (APT). The TEM results reveal that two types of LPSO phase (a bulky interdendritic phase and a plate-like matrix LPSO phase) are formed in the as-cast sample. Most of the LPSO phases are confirmed to be of the 14H type, with a smaller proportion being of the 18R LPSO. Further, the APT results reveal that the composition of the interdendritic LPSO phase is closer to that of the ideal 14H phase compared to the matrix LPSO phase, and both the interdendritic and matrix LPSO phases exhibit a Gd/Zn ratio of 2.5, thereby indicating a deficient Zn content compared to the ideal 14H phase (i.e., 1.3). In addition, the influence of the LPSO phases on the deformation behavior is investigated at different compressive plastic strains using electron backscatter diffraction (EBSD) analysis to reveal twinning and slip behavior during deformation. The results indicate that the LPSO phase induces additional work hardening in the late stage of deformation via the suppression of {101} compressive twinning and the activation of non-basal slip systems.

U2 - 10.1016/j.jma.2023.07.012

DO - 10.1016/j.jma.2023.07.012

M3 - Article

VL - 11.2023

SP - 2801

EP - 2810

JO - Journal of magnesium and alloys

JF - Journal of magnesium and alloys

SN - 2213-9567

IS - 8

ER -