The influence of cerium addition on the microstructure of AZ91 magnesium alloy and grain refinement mechanism
Liu S F
武汉理工大学
Cite this article:
Liu S F. The influence of cerium addition on the microstructure of AZ91 magnesium alloy and grain refinement mechanism. Acta Metall Sin, 2006, 42(4): 443-448 .
Abstract The effect of cerium addition on the microstructures of AZ91 magnesium alloy has been studied. It was found that a small amount of cerium addition to AZ91 magnesium alloy produced a large decrease in the α-Mg grain size. With increasing Ce addition, the amount of β-Mg17Al12 phase was decreased, and its size became dispersed fine. In addition, the rod-shaped or needle-like Al4Ce phases mainly distributed at grain boundaries have been observed in the AZ91 alloys with Ce addition. The grain refinement mechanism was investigated using EDS analysis and water-quenched microstructural observation. The results showed that the grain refinement of the AZ91 alloys containing Ce was mainly attributed to the addition of Ce generated constitutional undercooling at solidification interface front, consequently, increase in the number of nucleation. In addition, its restricting growth effect on the α-Mg crystals can result in the further grain refinement.
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