Abstract:The Mg–Zn–Y–Zr alloys with long-period stacking-ordered (LPSO) and W eutectic phases were investigated to develop new magnesium casting alloys. The temperatures for T6 heat treatment were selected based on the hardness and electrical conductivity measurements. The hot tearing susceptibility of the alloys with LPSO phase is lower than that of the alloys with W phase, which is associated with the freezing range of the alloys. However, the investigated alloys displayed the same fluidity. Under T6 conditions, increasing the Y content in the alloys resulted in increased yield strength, whereas other tensile properties were similar for the alloys. The corrosion resistance was higher for the alloys with LPSO phase compared to that of the alloys with W phase. Mg-2.5Zn-3.7Y-0.3Zr (mass fraction, %) alloy with LPSO phase possessed high castability and mechanical properties, with a corrosion rate of 2 mm/year.

Key words: magnesium alloy; casting; LPSO phase; W phase; fluidity; hot tearing susceptibility; corrosion rate