Abstract
A primary goal of the federal Bureau of Mines is to minimize the requirements for scarce mineral commodities through conservation and substitution of more abundant elements, such as iron and molybdenum. One example of this is the research effort to devise substitute materials for specialty alloys, thereby conserving nickel and chromium in high-volume stainless steels. As a possible substitute for the solid solution strengthening of chromium and nickel, the precipitation hardening characteristics of a number of binary iron- based systems in which laves phase precipitates, such as fe2mo, are formed were investigated. Several hardening responses were observed, but none were ideal. The fe-ta binary system had the highest magnitude of hardening, even with low alloy additions, and the fe-mo system had unique stability at temperature. Accordingly, the fe-mo-ta system was selected for study to determine if a ternary laves phase could combine hardening with long-term stability at elevated temperature. Hardening and stability were reflected in excellent elevated temperature, tensile, and stress rupture strengths. Future research will study ternary systems based on more abundant resource materials, such as the fe-mo-ti system, together with additions, such as aluminum and minimal chromium, to provide oxidation resistance.
