Test pieces were struck in 2011 and 2012 in the following combinations using newer Martha Washingon dies than found on J2180 combined with a shield reverse similar to regular issue coinage. Both sides show mottos with reversed or scrambled lettering, etc.
Additional information on this can be found in the "ALTERNATIVE METALS STUDY" submitted to the U.S. Mint by Concurrent Technologies Corporation.
Tests were also done for nickels and quarters as well.
Examples were struck in the following combinations:
1) Current copper plated zinc A190 (Jarden Zinc Products)
2) Aluminized Steel (Ryerson)
3) Aluminized Steel (Atlas)
4) 5052-H32 Aluminum-Magnesium (Aleris)
5) Copper Plated Steel (Jarden Zinc Products)
6) Copper Plated Steel (Royal Mint)
7) 430 Stainless Steel
8) 302 Stainless Steel (Carpenter Technology)
The report has images, usually of one side, for all of these combinations. Click on the thumbnail image to see a couple of these. The non-copper plated alloys are either a steel or a yellowish color.
It is unclear whether or not, the Mint would confiscate these should any turn up in collector's hands.
Photos courtesy of the U.S. Mint.