Forge-welding stainless will require a good flux to flux the chromium oxide scale that forms. In this respect I suggest you contact other damascus makers, rather than typical engineers who are profoundly in ignorance of damascus.
I presume you want the stainless part to be hard. I also suspect that you already know the hardenable stainless grades useful for knives, i.e. 440B or 440C, Crucible's 154CM, or the Japanese grades such as ATS-34, and several AUS whatever grades. Forging ranges for these stainless steels will be more narrow than for 5160.
410 stainless might suit for the lower carbon/softer part of the blade, but 410 is so low in chromium that now & again it rusts.
I don't know availability of stainless powders. But certainly stainless weld wire can be had at your local distributor. If you want an austenitic stainless, which will be soft (not even Rockwell C20) but nice & shiney, the most common stainless weld wire is AWS ER308, or just plain "308" weld wire. Nominal chemistry is about 22%Cr 11%Ni This is the wire used to weld 304 stainless, a.k.a."18-8" stainless, the stuff used to make pots & pans and most half-decent "silverware"
James Kelly