Influence of Fe addition on the formation of a quasicrystalline phase in bulk Al-rich AlMn base alloys

- Al-rich AlMn base alloys with different Fe content were prepared by wedge casting.
- Influence of cooling rates and Fe content on the quasicrystalline phase formation was studied.
- The addition of Fe to AlMn alloys improves the quasicrystal forming ability.
- Two-phase microstructure Al/quasicrystal can be formed at intermediate cooling rates.
- High hardness is obtained for microstructures containing fine Al/quasicrystal eutectic.

This work evaluates the effect of Fe addition on the formation of a quasicrystalline phase in the 94Al6Mn base alloys obtained by wedge casting. Different Mn to Fe ratios (1, 1.4, 2, 5) were used to estimate Fe content that leads to formation of a quasicrystalline icosahedral phase (I-phase) at the selected Al concentration (94 at.%). Based on the obtained results, Fe enhances I-phase nucleation in the studied ternary alloys compared to the non-modified binary composition. Although the maximum thickness of the cast wedge at which the I-phase was formed in the prepared alloys varied with Fe content, its nucleation was always limited to a certain range of cooling rates above 103 K/s. Hardness increased significantly for areas composed of Al matrix and I-phase particles. The highest HV values were obtained for parts of castings where the microstructure consisted of very fine I-phase/Al eutectic.