A unified approach to complex crystalline and so-called quasicrystalline phases in aluminium alloys

Recent developments in the complex and controversial, but fertile and fascinating field of aluminium-transition metal alloys are reviewed with particular reference to the so-called quasicrystalline phases and their rational approximants. Pauling’s several approaches to icosahedral phases on the basis of twinning in cubic crystals with large unit cells are described and examined along with the difficulties in checking the structures proposed by him. A new unified crystallographic approach is presented by the author, starting with icosahedral atomic clusters in concerned alloy melts, and it is shown that this integral approach leads to a reasonably good understanding of the interrelationship between the numerous known solid phases in aluminium alloys, including icosahedral phases, decagonal phases and their rational approximants. DEDICATED TO THE MEMORY OF PROFESSOR LINUS PAULING (1901–1994).