Systems Design Approach to Low-Cost Coinage Materials

Area of Science:

• Materials Science
• Computational Engineering
• Alloy Design

Background:

• Current US coinage alloys face challenges related to raw material costs.
• Seamless replacement coinage alloys require matching specific physical and chemical properties.
• Existing production processes must be compatible with new alloy designs.

Purpose of the Study:

• To design novel, low-cost coinage alloys as replacements for current US coin materials.
• To ensure new alloys possess comparable yield strength, work-hardening behavior, electrical conductivity, color, corrosion resistance, and wear resistance.
• To integrate computational tools, including CALPHAD-based models, into the alloy design process.

Main Methods:

• Utilized a systems approach within an Integrated Computational Materials Engineering (ICME) framework.
• Developed CALPHAD-based models for electrical conductivity and color prediction.
• Designed, produced, and characterized three prototype coinage alloys.

Main Results:

• The alloy design process revealed a trade-off between minimizing raw material costs and achieving desired color properties.
• Characterization of the prototype alloys demonstrated good agreement with the initial design objectives.
• Successfully designed alloys compatible with existing coinage production processes.

Conclusions:

• New low-cost coinage alloys can be designed using computational materials engineering.
• Balancing cost reduction with property requirements, particularly color, is crucial in alloy development.
• The developed alloys show promise as viable, cost-effective replacements for current coinage materials.