Precipitates in a quasicrystal-strengthened Al-Mn-Be-Cu alloy

In this work, an Al-Mn-Be-Cu alloy was studied containing a primary and eutectic icosahedral quasicrystalline phase in the as-cast microstructure. Special attention was given to a transmission electron microscopy investigation of precipitates formed within the aluminium solid solution (Alss) at different temperatures. At 200 °C, only binary Al-Cu precipitates (θ′) were formed. At 300 °C, icosahedral quasicrystalline (IQC) precipitates prevailed with a crystallographic orientation relationship with the Alss. The rods of the T-phase (Al20Mn3Cu2) which were precipitated above 400 °C, also had a specific orientation relationship with the Alss. The primary and eutectic IQC microstructural constituent started to transform rapidly to the T-phase and Be4Al(Mn,Cu) at 500 °C.