Effects of Zn and Y on hot-tearing susceptibility of Mg–<i>x</i>Zn–2<i>x</i>Y alloys

Abstract

The effect of Zn and Y on hot-tearing susceptibility (HTS) of Mg– xZn–2 xY ( x = 1, 1.67, 2.67) alloys is investigated. It is found that the microstructure of the alloys is mainly composed of α-Mg, long-period stacking-ordered (LPSO) phase and W-phase. Both theoretical and experimental results illustrated that HTS of the investigated alloys is in the following order: Mg–1Zn–2Y &gt; Mg–1.67Zn–3.34Y &gt; Mg–2.67Zn–5.34Y. For Mg–2.67Zn–5.34Y alloy, LPSO phase content reaches at the maximum and its grain size reaches at minimum of 16.4 µm, and the pinning effect of the LPSO phase on grain boundaries is considered to be an important reason for reducing HTS of the alloy.