Orthorhombic <i>ε</i>-phases and transitional structures in Al—Pd—(Fe)

Abstract

Abstract The results of an investigation of the structures formed in the range of about Al 73 Pd 27 to Al 76 Pd 14 Fe 10 by electron diffraction and high-resolution transmission microscopy are reported. The orthorhombic ε 6 , ε 16 , ε 22 and ε 28 phases were observed in specific compositional sub-ranges. Their lattice parameters a ≈ 2.34 and b ≈ 1.62 nm are essentially the same while the c parameters are ≈1.23, 3.24, 4.49 and 5.70 nm, respectively. Apart from these regular structures, also structures aperiodic along the c -direction are revealed at intermediate compositions. Thus, inside the wide ε -phase range only slight continuous variations of the orthorhombic a and b cell parameters are accompanied by complicated modulations of the c cell parameter.