Formation of quasiperiodic and related periodic intermetallics in alloy systems of aluminum with transition metals

Quasiperiodic phases (quasicrystals) have been found in numerous alloy systems of aluminum with transition metals (TM) between about 60 and 85 at.% Al. In binary Al–TM systems only metastable quasicrystals were observed, while in several ternary systems containing Cu, Ni or Pd the quasicrystals are stable. Many stable and metastable periodic phases formed in these compositional ranges exhibit structural relations to quasicrystals. Studies of these phenomenona have stimulated extensive investigation or revision of the high-Al regions of the ternary alloy systems belonging to the Al–Cu–TM, Al–Ni–TM and Al–Pd–TM groups. These studies are reviewed here.