Icosahedral aluminum–transition-metal alloys

We have used x-ray and electron diffraction to study the icosahedral phase in rapidly quenched alloys of Al with Mn, Re, Cr, Ru, V, Mo, and W. We also find negative results in searches for the icosahedral phase in various other transition-metal alloys. Addition of small amounts of Si and Ru to Al-Mn and Al-Cr alloys appears to enhance stability of the icosahedral phase. We discuss the role of atomic packing, electronegativity differences, and electronic band structure in stabilizing this phase.