Multicomponent Si-Based Amorphous Alloys Produced by Melt Spinning and Their Crystallization Behaviour

Abstract

By the addition of some definite transition metals Ni, Cr and Zr to the Si-Al-Fe system, the maximum Si content for formation of an amorphous single phase was extended to 50 and 55 at% Si. The Si-based amorphous alloys are characterized by high values of electrical resistivity (11.7-12.3 μΩm) and hardness (- 930HV). Their crystallization temperatures exceed 700 K, which is higher by about 100 K than those for Si 43 Al-Fe-Cr and Si 45 Al-Fe-Ni quaternary alloys. During heat treatment of an amorphous Si 55 Al 20 Fe 10 Ni 5 Cr 5 Zr 5 alloy at the temperature above the crystallization temperature, a 6-component Si 10 Al 4 Fe 2 NiCrZr phase with a tetragonal structure having lattice parameters a=0.6890 nm and c= 0.9402 nm is formed as a main constituent phase. The difficulty of the precipitation of the multicomponent crystalline phase with the large volume of unit cell during rapid solidification is presumed to be the main reason for the formation of the Si-based amorphous phase.