Synchronized collapse and formation of long-period stacking and chemical orders in Mg85Zn6Y9

Phase transformation of the long-period stacking order (LPSO) synchronized with the chemical concentration in Mg85Zn6Y9 has been investigated during both heating and cooling via in situ X-ray diffraction analysis. With increasing temperature, above 800 K, 10H-type LPSO phase collapsed firstly. 10H structural modulation collapsed earlier than the chemical modulation of 5 layers per period. The in-plane ordering consisted of aligned L12-type clusters vanished before the collapse of chemical and structural modulation of 18R-type LPSO. After, the chemical and structural modulation of 18R-type LPSO show synchronize collapse.During cooling, the 14H-type LPSO emerged in addition to the 18R-type LPSO. The growths of chemical and structural modulation start at the same temperature. After that, the formation of in-plane order consisting of aligned L12-type Zn–Y clusters emerged.