Modulated structures and GP Zones in Al-Mg Alloys

The formation of modulated structures and GP zones in Al-Mg alloys aged at low temperatures was investigated using the mechanical properties, electrical resistivity measurements, and high resolution electron microscopy. It was shown in TEM investigations that a modulated structure was present in Al-10 wt pct Mg alloys at the beginning of low temperature aging which grew into GP zones having the Ll₂ structure distributed periodically along the [100] direction. The miscibility gaps for GP zone formation and the spinodal temperature were determined from the results of resistivity measurements. It is suggested that in Al-Mg alloys spinodal decomposition can occur at the beginning of low temperature aging. Y. KOJIMA, formerly with Tokyo Institute of Technology