Effect of solute Mg on grain size of aluminium alloys

The effect of solute Mg on grain size in Al–Mg alloys was investigated. Mg provides a grain refining effect for aluminium alloys that is retained until the eutectic point. While the inverse relationship between the grain size and the growth restriction factor is confirmed for hypoeutectic Mg concentrations, the monotonic increase of the latter even when the growth restriction effect gradually deteriorates evidences a rather poor correlation with the grain size in Al–Mg alloys. The correlation between the grain size and the solidification interval in Al–Mg alloys is not a good one, either. Hence, the solute effect depends on the system and appears to be too complex to be accounted for by a single parameter.