STRUCTURAL INVESTIGATIONS OF THE AMORPHOUS ALLOY AL30GE70 UNDER HIGH-PRESSURE

The structural behavior of the amorphous phase Al30Ge70, obtained by p ressure quenching, has been investigated under pressure by in situ ene rgy dispersive x-ray diffraction (EDXD) using synchrotron radiation. A t p approximate to 5 Cpa there is a reversible transition from the amo rphous state to a crystalline state with simple hexagonal (sh) structu re. This gamma phase is stable up to 47 Cpa. At this pressure a transi tion to a hexagonal closed-packed structure takes place. The behavior of Al30Ge70 under pressure is discussed in connection with structural transformations of group-IV elements and III-V compounds.