Effects of Y and Zn/Y on hot tearing susceptibility of Mg–Zn–Y–Zr alloys

Abstract

The effects of Y and Zn/Y on hot tearing susceptibility (HTS) of Mg–6.5Zn– xY–0.5Zr ( x = 4, 9, 12 and 18) and Mg–5Zn–13.5Y–0.5Zr alloys were investigated herein. The results illustrated that HTS of the investigated alloys decreased in the following order: Mg–6.5Zn–4Y–0.5Zr > Mg–6.5Zn–18Y–0.5Zr > Mg–6.5Zn–9Y–0.5Zr > Mg–6.5Zn–12Y–0.5Zr > Mg–5Zn–13.5Y–0.5Zr. The results also showed that HTS of the α-Mg-based alloy containing only LPSO phase was lower than that of the alloy containing only W-phase and (I+W) or (W+LPSO) mixed secondary phases. This was attributed to the coherence relationship between LPSO phase and α-Mg, and the bridging effect of LPSO phase.