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Systems Design Approach to Low-Cost Coinage Materials

  • Eric A. Lass
  • Mark R. Stoudt
  • Carelyn E. Campbell
Thematic Section: 4th World Congress on Integrated Computational Materials Engineering

Abstract

A systems approach within an integrated computational materials engineering framework was used to design three new low-cost seamless replacement coinage alloys to reduce the raw material cost 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 designed alloys were required to use current production processes. CALPHAD-based models for electrical conductivity and color were developed to integrate into the system design. 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.

Keywords

CALPHAD ICME Materials design Coinage alloy 

Notes

Acknowledgments

Funding for this work was provided by an Interagency Agreement between the United States Mint and the National Institute of Standards and Technology, HQ14RA-38 NISTMOD. 001 (IA# 1404-642-01). The authors gratefully acknowledge Tony Ying of the United State Mint for providing stamping, vending machine testing, and additional color and electrical conductivity measurements.

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Copyright information

© The Minerals, Metals & Materials Society 2018

Authors and Affiliations

  1. 1.Materials Science & Engineering Division, Material Measurement Laboratory, U.S. Department of CommerceNational Institute Standards and TechnologyGaithersburgUSA

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