Microstructural Factors Affecting the Deformation Behavior of Mg₁₂ZnY LPSO-Phase Alloys

Abstract

Microstructural factors that govern the plastic deformation of the long-period stacking ordered (LPSO) phase were clarified. The decrease in length of the long-axis for the plate-like shape of LPSO-phase grains increases the yield stress of the alloy in which basal slip is predominant in deformation. On the other hand, the yield stress tended to increase as the thickness of the plate-like shapes of the grains decreased for the alloy in which the formation of deformation kinks carried the strain.

Non-Basal Slip Systems Operative in Mg₁₂ZnY Long-Period Stacking Ordered (LPSO) Phase with 18R and 14H Structures

“…2 Temperature dependence of the yield stress of the DS and extruded LPSO phase specimens. 13,23,25) The yield stresses of the specimens in which the operation of non-basal slip was partly observed were plotted by solid symbols.…”

“…25) In order to identify the slip plane of the operative non-basal slip, a so-called two-face slip trace analysis, which is usually conducted in a single crystal, was attempted in the deformed DS crystal. Figures 3(a), 3(b) show the OM images of the non-basal slip traces introduced in the grains located at the side edge of the DS specimens with the 18R structure in deformation at 400°C.…”

“…In addition, the operation of non-basal slip was observed under the limited conditions including the high-temperatures. 13,25) Therefore, it is extremely important to identify the nature of the non-basal slip system in order to improve the workability of high-volume-fraction LPSO phase alloys and to control the high-temperature deformation behavior of Mg-based alloys containing an LPSO phase. However, little information on non-basal slip in the LPSO phase is available at present; the slip plane, the Burgers vector of the dislocation, and the critical resolved shear stress (CRSS) are all unknown due to the difficulty in making an LPSO phase single crystal.…”