Formation of quasicrystals through peritectoid reactions from a nonequilibrium cubic phase prepared by mechanical alloying

Quasicrystals involving decagonal and icosahedral phases were formed, through two peritectoid reactions on low-temperature annealing, from a nonequilibrium cubic phase prepared by the ball milling of a mixture of equilibrium cubic phase and A1 powders in Al -Cu -Co and Al-Cu-Fe systems. In both systems, the peritectoid reaction between residual A1 and preliminary milled nonequilibrium cubic phase occurred first to form tetragonal Al⁷Cu²(Fe, Co) at 623 K. Subsequently, the same reaction between these tetragonal and the nonequilibrium phases occurred to form the quasicrystals at 773 K.