The effect of grain refiners on intermetallic phases in commercially pure aluminum was investigated using a DC simulator,which has similar cooling conditions to the subsurface region of DC cast ingots.An AA1xxx alloy was cast with different addition levels of AlTiB,AlTiB and AlB type grain refiners.The cast structure and intermetallic phases were characterized by macro-etching,SEM and X-ray diffraction analysis.It was found that TiB_2 and TiC particles promote the formation of the metastable Al_mFe phase and enlarge the fir-tree zone.The nucleation sites of intermetallic phases were observed and analyzed by using deep-etching and SEM techniques.the roles of TiB_2 and TiC in promoting the Al_mFe phase in the ingot structure were discussed.
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