Observation of large Equilibrium Phase of Al-Mg-Si Alloys

The precipitation sequence in Al-Mg-Si alloy is generally accepted as supersaturated solid solution GP-zone β β β (Mg2Si). The effect of Ag or Cu in Al-Mg-Si alloy was reported in our previous work. There is little report about effect of Ag or Cu on the metastable phase and equilibrium phase in this alloy the system. Hexagonal plate like β-phase and Q-phase were observed the Cu added alloy. This hexagonal-shaped β-phase has unique orientation relationship to the Al matrix. This work was performed to compare the shape of effect of the additional elements on the equilibrium phase. The hexagonal shape precipitate was observed in Cu or Ag added alloys aged at 673K.