Synthesis and Investigation of Quaternary Quasi-Crystalline Phase in Al – Cu – Fe – Cr Alloys

Abstract

Formation of a quasi-crystalline phase under rapid solidification and heat treatment of alloys of the Al – Cu – Fe – Cr system is studied. The study is performed by x-ray diffractometry, optical, scanning and transmission electron microscopy and differential scanning calorimetry. It is shown that the quasi-crystalline Al₆₅Cu₂₀Fe₁₀Cr₅ phase is a mixture of icosahedral and decagonal phases. The substitution of iron with chromium destabilizes the icosahedral I-phase and promotes formation of a decagonal d-phase. After quenching from 880°C, the Al₆₄Cu₂₄Fe₁₀Cr₂ alloy acquires a pure I-phase, and the Al₆₄Cu₂₄Fe₈Cr₄ alloy acquires a d-phase.