A MODEL FOR THE DEFORMATION-BEHAVIOR OF AMORPHOUS-ALLOYS WITH APPLICATION TO THE WEAR LOADING OF THE FILM-ON-SUBSTRATE GEOMETRY

One method of addressing practical wear problems is via the creation of wear resistant films on the exposed surface by various surface modification techniques. A class of materials produced by such techniques, amorphous metals, is known to exhibit mechanical properties consistent with good wear resistance. In this paper we present a model for the mechanical behavior of these materials that is mechanistic in nature, yet sufficiently simple to allow treatment of the film-on-substrate geometry. The Eyring rate theory is used as a basis to describe the deformation rate, and agreement with stress sensitivity and activation energy data is shown to support this approach. The local creation of excess volume and its relaxation are integral parts of the deformation process in these materials. The kinetics of relaxation is analyzed, and the physical attributes of that process are examined. The effects on deformation of a hydrostatic stress component in the wear loading mode are addressed. The relation of all these factors to strain localization in the film is also studied. The strength of an amorphous film produced by ion implantation is estimated and correlations with plastic flow depth are established. Methods of predicting the wear responses of particular materials in this geometry are presented and compared with published wear data. © 1990 Springer-Verlag New York Inc.