Effect of Iron and/or Carbon on the Grain Refinement of Mg-3Al Alloy

摘要

The effect of iron on the grain refinement of Mg-3Al alloy modified with and without carbon powder has been investigated in the present study. Significant grain refinement could be obtained for Mg-3 mass%Al alloy modified with either Fe or carbon. The Al-C-O and Al-Fe particles were observed which should be the potent nuclei for Mg grains. The high segregating power of Fe was also proved as an important factor which determines the grain size of Mg-Al alloys. Refining efficiency could be further obtained by the combination of Fe and carbon. Both Al-C-O-Fe-rich and Al-Fe-rich intermetallic particles were observed in the samples modified by the combination of Fe and carbon. The Al-C-O-Fe-rich intermetallic particles should play a very positive role in grain refining for Mg-Al alloys. The combination of Al-C-O-Fe and Al-Fe intermetallic compounds produced more powerful nuclei for Mg grains, and thus caused grain refinement.