Duritanium Polyalloy
From Star Trek : Freedom's Wiki
Duritanium Polyalloy was a strong type of alloy used for construction and based in duritanium.
An alien probe destroyed by a Cardassian ATR-4107, dubbed "Dreadnought", was composed primarily of duritanium polyalloy. When the debris was later discovered by the USS Voyager, it was noted that very few weapon types were capable of damaging a spacecraft with a duritanium hull to that extent. (VOY: "Dreadnought")
