Microstructure and properties of melt-spun Si-Al-Ge-transition metal amorphous alloys containing nanocrystalline Ge particles

Abstract

The effect of Ge addition on the microstructure and some properties was examined for rapidly solidified Si-Al-TM alloys. In particular, the addition of Ge to Si55Al20Fe10Ni5Cr5Zr 5 alloy causes a change to a mixed structure in which fine Ge solid solution particles are dispersed homogeneously in an amorphous matrix. The size, volume fraction and composition of the particles depend on Ge concentration in the alloy. Fine particles, with a size less than 10 nm, were obtained in the range from 5 to 10 at% Ge. These alloys are characterized by high values of hardness (935-1085 Hv) and electrical resistivity (11.0-12.6 μΩm). Owing to the change in the matrix composition, the crystallization temperature increases with increasing Ge content and the highest value reaches 767 K. The exclusion of Ge from the amorphous phase resulted from the complicate interaction between constituent elements.