A study of the Al–Pd–Co alloy system

Partial isothermal sections of the Al–Pd–Co phase diagram at 1050 and 790°C are presented. In contrast to Al–Ni–Co no stable quasicrystals were found under the investigated conditions. Instead, at the compositions corresponding to the high-Co limit of the Al–Ni–Co decagonal phase a periodic phase closely related to the decagonal phase is formed. Orthorhombic “Al3Pd”, whose structure is known to resemble quasicrystals, extends up to 17 at.% Co and exhibits structural variations with composition. At the Al concentrations slightly lower than Al3Pd(Co) several new ternary periodic phases were found.