Synthesis of icosahedral phase during cold working and annealing of elemental multilayers in the Al–Cu–Fe ternary system

The icosahedral phase formation and associated structural evolutions in the Al–Cu–Fe ternary system have been examined through the repeated cold rolling and folding (R&F) process of elemental foils with a target composition of Al62.5Cu25Fe12.5 (at.%). Upon early increments of the rolling and folding cycles, the elemental Fe foil was dispersed through the refined Al and Cu layers. When the rolling and folding step reached 40 cycles the Al2Cu phase has been observed, however, no ternary phases were identified even upon additional R&F cycles. The stable icosahedral phase (i-phase) could be obtained after isothermal annealing of the R&F processed specimens at 650 and 750 °C. The phase evolution during repeated cold R&F process of the Al–Cu–Fe system and upon heat-treatments are discussed in terms of the formation and dissolution of the Al2Cu and Al7Cu2Fe phases.