Systems Design Approach to Low-Cost Coinage Materials

Abstract

A system design approach using an Integrated Computational Materials Engineering (ICME) was used to design three new low-cost seamless replacement coinage alloys to reduce the raw material of the current US coinage alloys. Maintaining compatibility with current coinage materials required matching the currently used alloy properties of yield strength, work-hardening behavior, electrical conductivity, color, corrosion resistance and wear resistance. In addition, the design alloys were required to use current production processes. CALPHAD-based models for electrical conductivity and color were developed to integrate into the system design approach. Three prototype alloys were designed, produced and characterized. The design process highlighted the trade-off between minimizing the raw material costs and achieving the desired color properties. Characterization of the three prototype alloys showed good agreement with the design goals.