2015 Volume 56 Issue 7 Pages 906-909
Stability of long-period stacking ordered (LPSO) structures of Mg-Zn-Y ternary alloys at elevated temperatures was examined by multicolor synchrotron radiation small- and medium-angle scattering/diffraction. The LPSO structures directly melted during heating, and the formation of LPSO was observed from supercooled liquid. The temperatures of complete dissolution and the onset of formation of LPSO phases were measured by monitoring the first diffraction peak of 14H, 18R and 10H compositional modulation. The stability of composition modulation in c axis direction was found to be the same as that of L12 cluster ordering in the segregation layer in both heating and cooling processes, i.e., dissolution and formation. Supercooling of LPSO was obtained for the heating/cooling rate of 10 K/min.