Effect of long-period stacking ordered phase on hot tearing susceptibility of Mg–1Zn–xY alloys

Abstract

The effect of long-period stacking ordered (LPSO) phase on hot tearing susceptibility of Mg–1Zn–xY serial alloys were investigated experimentally using a home-made T-type hot tearing mold. The characteristic parameters related to HTS during the solidification process were calculated by thermal analysis. The microstructure and morphology of the crack zone were characterized by optical microscope (OM), scanning electron microscopy (SEM) and electron dispersive spectrometer (EDS), and the phases of the alloys were analyzed by X-ray diffraction (XRD). The result showed that the long-period stacking ordered (LPSO) phase formed when m (Zn)/m (Y) < 1, and the LPSO content increased with increasing of Y. The presence of the LPSO phase in Mg–1Zn–xY alloys could benefit the hot tearing refilling and decrease the HTS of the alloys. With increasing the content of LPSO phase, the HTS of the alloys decreased. LPSO phase increased the skeleton strength, and reduced the HTS of Mg–1Zn–xY alloys.