The influence of rare earth metals on the structure of some rapidly solidified Ge- and Si-based alloys

Abstract

Ge-rich amorphous alloys containing up to 70 at.% Ge were produced by the optimization of the Al, Cr and RE (RE: rare earth metals) content. Contrary to the Ge-based alloys, no positive influence of RE additions on the glass forming ability (GFA) of the Si–Al–TM and Si–Al alloys (TM: transition metals) was found. As no split of the first broad peak is seen in the X-ray diffraction patterns taken from the amorphous phase of the Ge–Al–RE alloys, one can suggest that such a feature observed in the Ge–Al–TM and Ge–Al–TM–RE alloys is affected by the presence of 3d TM. Peritectic-type phase transformation, amorphous phase + unknown crystalline phase 1→ unknown crystalline phase 2 , was observed in the Ge 60Al 25La 15 alloy and studied. The metastable crystalline phase 2 (Ge 12Al 5La 3) was found to have a tetragonal lattice with lattice parameters of a=0.559 nm and c=0.528 nm .