Phase Stability of Amorphous Intermetallic Alloys

摘要

Phase stability of amorphous intermetallic alloys, in terms of both formation and thermal stability, can be related to the alloy chemistry of the crystalline counterpart: the intermetallic compounds. The formation of the amorphous alloys is generally favored by the composition range in which the complex-structured intermetallic compounds and nearby eutectic point are present. The relative thermal stability of the amorphous intermetallic alloys, expressed by the reduced crystallization temperature, T/sub rc/, (T/sub rc/= T/sub c/T/sub m/, where T/sub c/ is the crystallization temperature exp 0 K, and T/sub m/ the melting temperature of the crystallized phase exp 0 K) increases with the increasing of the structural complexity of the crystalline counterparts. Based on recent data of amorphous intertransiton metal alloys, T/sub rc/ increases rapidly from less than 0.1 for the simple structures of bcc, fcc, or hcp, to nearly 0.4 for more complex structures such as A15, Laves-, sigma- and CaCu sub 5 -phases up to 0.6 for highly complex structures of eta-, delta-, and mu -phases. It can therefore be argued that alloy principles for the equilibrium compounds can be applied to the phase stability of the amorphous intermetallic alloys. (ERA citation 05:012177)