Prediction of the formation of binary metal-metal amorphous alloys by ion implantation

Data from the literature on 25 binary metal-metal alloy systems known to have been produced by ion implantation, show that in 15 cases amorphous alloys have been formed, and in 10 cases not. An empirical straight line relationship between the chemical potential and the electron density at the boundary of the Wigner-Sietz atomic cell, has been shown to separate most of the formed and unformed amorphous alloys into two regions on a graphical plot. Similarly, a chemical co-ordinate scheme combining chemical potential and electron density into one function and relating this to a function of the interatomic distances of the binary components, produces a curve which again separates the formed and unformed amorphous alloys with considerable success. The success achieved is certainly greater than that of a scheme which assumes that the ratio of the radius of the implanted ion to that of the host metal ions is the only factor determining glassy alloy formation. Using the criteria derived in this study, predictions of glassy alloy formation can be made with some confidence for a number of systems. (U.K.)