Solidification behavior of cast TiB2 particulate reinforced Mg composites

The solidification behavior of the cast TiB2 particulate reinforced AZ91 composite, including the cooling curve, microstructure and grain refinement effect, was investigated in the present study. Compared with the AZ91 alloy, the composite possessed lower nucleation temperature of primary alpha-Mg, almost the same eutectic reaction temperature and faster cooling rate during the total solidification time. The TiB2 particulates were pushed into the last solidified region and were surrounded by the eutectic Mg17Al12. The grain refinement effect in the TiB2/AZ91 composite can be attributed to the growth restriction effect exerted by TiB2 particulates and the faster cooling rate of the composite.