Effect of Si addition on the formability of the icosahedral quasicrystalline phase in an Al65Cu20Fe15 alloy

The effect of Si addition on the icosahedral forming Al65Cu20Fe15 alloy was investigated. Conventional casting and melt spinning were employed with the addition of Si element. As Si was added up to 5 at.% replacing the Al atoms, the volume fraction of the i-phase gradually decreased. However, with increasing Si content further up to 15 at.%, an 1/1 cubic approximant phase formed instead of the i-phase. After heat treatment at 750°C for 3 h, the volume fraction of the β-phase increased in an Al64Cu20Fe15Si1 alloy, while the volume fraction of the 1/1 approximant phase increased in an Al50Cu20Fe15Si15 alloy. The Al50Cu20Fe15Si15 alloy showed a relatively high hardness and fracture toughness compared to the other Si containing Al–Cu–Fe alloys.