When I was grinding out my Armorer today I noticed that the Level 16 Outfitter reciepe for Blacked Iron Halbred does not require Blackened Iron Cluster to make. The recipe only needs an Iron Edge as opposed to the Blackened Iron component.
Crafting one to verify that it spits out a legendary blacked iron halbred and it does.
I made some components and such and while the recipe does request an iron edge, it leaves the box empty and says you don't have any. it won't let you combine the Halbred. It looks to be doable, but it is not.