Attainment of quasicrystalline phase in Al-Cu-Fe alloy via melting and mechanical alloying

Al ₆₂Cu _25.5Fe _12.5 (A) and Al ₆₅Cu ₂₀Fe ₁₅ (B) alloys were fabricated via melting and experimentally studied in both as-cast and annealed conditions. Alloy (B) was also fabricated using mechanical alloying and an annealing treatment. The melted alloys were characterized to investigate the distribution of alloying elements Fe and Cu on the icosahedral and coexisting phases, as well as the hardness of all phases. The as-cast alloys showed the highest amount of icosahedral phase with up to 47% of ingot (A), but this increased after heat treatment to 99% and 75% of ingots in (A) and (B) alloys respectively. During heat treatment the iron content was increased in all phases, while the copper content decreased. As a consequence, the hardness of the icosahedral phase increased by 23% in (A) Al ₆₂Cu _25.5Fe _12.5 alloy and 33% in (B) Al ₆₅Cu ₂₀Fe ₁₅ alloy. On the other hand, the effect of heat treatment on samples obtained from mechanical alloying caused a modification in the iron and copper contents, leading to the formation of iron-rich phases such as λ-(Al,Cu) ₁₃Fe ₄ phase for all milling times and the icosahedral phase after 35 h.