Precipitation of Nanogranular Ge Particles in Rapidly Solidified Ge-Al-TM-Si (TM-Transition Metals) Alloys

Abstract

It has been reported that an amorphous phase is formed in rapidly solidified alloys of Al-Ge-TM (TM-transition metals) systems. Among the above mentioned systems, the alloys with a homogeneously amorphous structure in wide composition ranges were found in the Al-Ge-Fe, Al-Ge-Cr, Al-Ge-Mn and Al-Ge-Co systems. It also has been recently found that the composition range of an amorphous single phase in the Si-Al-Fe system was extended from 40 to 55 at.% Si by the addition of some transition metals namely Ni, Cr and Zr. Several new Si-based amorphous alloys were obtained. Since Ge belongs to the same periodic group as Si in the periodic table and a similar composition range for amorphous phase formation was found in the Al-Ge-TM and Al-Si-TM systems, the mutual influence of several transition metals on the composition range for the existence of the amorphous phase in the Ge-Al-TM system was studied in the present work. This paper is also intended to present the change in the microstructure of the Ge-based alloys from amorphous to amorphous+c-Ge (c-Ge-crystalline Ge) by the addition of Si.