Compositional Dependence of the Thermal Stability and Related Properties. of Metallic Glasses I: T(g) for Ca(.65)M(.35) and Zr(.4750Cu(.475)M(.05) Glasses

Ternary alloy glasses have been studied to obtain T sub g values for binary Ca glasses not displaying a glass transition. The results show that for Ca.65M.35 glasses T sub g depends on alloy valence and size; some correlations to phase diagram features such as the solidus temperature and the melting points of the phase CaM2 were also observed. It was also shown that for first long period transition metal additives to a Zr.50Cu.50 glass the changes of T sub g and T sub c are closely related to each other and, jointly, to the elastic moduli and melting points of the additives; the changes of T sub g are in general agreement with the predictions of an expression for T sub g which is based on a modification of the Lindemann melting point formula appropriate for the glass transition. The present results suggest that the properties controlling the thermal stability of glasses are additive when transition metal elements are added to a binary glass such as Zr-Cu, while interaction terms must be considered for non-transition metal addition elements as well as for most Ca-M glasses. The study of the thermal stability (and elastic properties) of metallic glasses may provide a general approach enabling one to determine the bonding effect of alloying additions at low and high levels without the restrictions on single phase formation imposed by the phase diagram.