Effect of iron content on the occurrence of Al-Fe-Si intermetallic phases in 6063 aluminum alloy ingots

The effect of iron content raging from 0.1 to O.5 mass% on the occurence of A1-Fe-Si intermetallic compound particles in a 6063 aluminum alloy was investigated in the as-cast state using X-ray diffraction and transmission electron microscopy (TEM). The compound particles were extracted from the ingot sby the thermal phenol method. In the 0.1% Fe alloy, monoclinic ?, hexagonal a and simple cubic a phases were observed. When the iron content increased to 0.2% the relative frequency of the β phase sharply increased to about 80% and became the main phase. In contrast, in the 0.3%Fe alloy with additional iron, the relative frequency of the ? phase decreased to about 20% , while that of the a phase increased to about 70%. When the iron content was 0.5% above the specified iron content, this tendency became remarkable, and no β phase was observed. As mentioned above, it is found that a slight change in the iron content of this alloy causes considerable changes in the relative frequency of the Al-Fe-Si intermetallic phase.