Effects of processing parameters and addition of flame-retardant into moulding sand on the microstructure and fluidity of sand-cast magnesium alloy Mg-10Gd-3Y-0.5Zr

this study, the effects of processing parameters (such as pouring temperature and mould pre-heating temperature) and flame-retardant content on the microstructure and fluidity of sand-cast magnesium (Mg) alloy Mg-10Gd-3Y-0.5Zr (GW103K) were systematically investigated. It was found that the increase of pouring temperature leads to coarsened microstructure and decreased fluidity of sand-cast GW103K alloy. Increase of mould pre-heating temperature incurs coarsening of as-cast microstructure and increase of fluidity. The addition of flame-retardant into moulding sand has a negligible influence on the microstructure of sand-cast GW103K alloy. With the increase in flame-retardant content, fluidity of the alloy initially increases and then decreases. The optimized process parameters and flameretardant addition were obtained to be pouring temperature of 750 degrees C, mould temperature of 110 degrees C, and flame-retardant addition of 1%. The fire retardant mechanism of moulding sand was determined. (C) 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.