Synthesis and magnetic properties of Al-Cu-Fe quasicrystals prepared by mechanical alloying and heat treatment

Elemental powder mixtures of Al, Cu, and Fe with nominal composition of Al65Cu20Cu15 were proceeded in a planetary ball mill for up to 5 h. Phase analysis of as-milled powders shows that only diffraction peaks of metallic elements were detected after milling for 60 min. The long milling times resulted in formation of an Al (Cu, Fe) solid solution (beta-phase), but no icosahedral quasicrystalline phase (i-phase). To induce solid-state transformation, milled powders were annealed at 600-700 & DEG;C for 4 h. i-phase, beta, and omega-Al7Cu2Fe1 phases were detected in samples milled 5-45 min. The maximum amount of i-phase was obtained after milling for 15 min, annealing at 700 & DEG;C and after milling for 30 min, and annealing at 650-700 & DEG;C. The annealed powders present soft ferromagnetic behavior at room temperature, but the magnetic loss was reduced with the increase of the i-phase and its size and reduced amounts of beta and omega phases.