http://mintnewsblog.com/2014/12/us-mint ... -congress/
"In light of these concerns, the Mint now seems to be focusing research on “seamless” materials that would not represent a change in electromagnetic signature eliminating the switching costs to the private sector. The leading candidate seems to be an alloy of 80% copper and 20% nickel. Basically, this would only modestly shift the proportions of metals in the current nickel, dime, and quarter to reduce the copper component.
The Mint’s conclusions stated that there are no alternative metal compositions to reduce the unit cost of the cent below its face value. The prospect or potential of eliminating the denomination was not mentioned or addressed."