Crystal–quasicrystal transition depending on cooling rates in directionally solidified Al–3Mn–7Be (at.%) alloy

• Al–3Mn–7Be (at.%) alloy is directionally solidified at various growth velocities.
• A transition is observed from λ-Al4Mn to H1 phase, and then I-phase.
• A close structural relationship between λ-Al4Mn and H1 phase is obtained.
• The structures of primary and eutectic I–AlMnBe phases are characterized.
• The addition of Be promotes the formation of I-phase.

The transition of primary phases from the crystalline approximant phase to icosahedral quasicrystal phase (I-phase) is observed in the directional solidified Al–3Mn–7Be (at.%) alloy. The structures of I-phase and approximant phases are characterized by SEM, TEM and HRTEM. The addition of Be significantly enhances the formation ability of I-phase, combining with the directional solidification method where the growth rates and temperature gradients can be separately controlled, giving rise to a promising way to prepare quasicrystal-reinforced Al-matrix composite.