Tensile strengthening of a Mg alloy containing 25-vol% LPSO by hot extrusion revealed by neutron diffraction

Harjo, S.   ; Gong, W.   ; Aizawa, Kazuya  ; Kawasaki, Takuro   ; Yamasaki, Michiaki*; Kawamura, Yoshihito*

Interesting mechanical properties changes were found in MgZnY alloy containing about 25-vol% long-period stacking ordered phase (LPSO) in the HCP structured matrix (Mg), by hot-extrusion. In situ neutron diffraction measurements during tensile loading were conducted on three MgZnY alloys with different processes: as-casted, and after hot-extrusion at 623 K with extrusion ratios of 5.0 and 12.5, to elucidate the relation between the changes in microstructure by hot-extrusion with the changes in mechanical property. The yield strength of Mg increased by the hot-extrusion, but when the extrusion ratio increased the Mg yield strength ironically decreased. LPSO was found to be strengthened monotonically as the extrusion ratio increased.