Quoted from Devin Thomas:
Is damascus better than a single steel?
"In short, we don't know, though there are plenty of theories to wonder about, there has been no major testing done on damascus to find out. Any testing that has been done hasn't been extensive enough to prove anything, but there has been a very little testing done. There are many possible advantages;for example, O1 is a very wear resistant steel, while 15N20 is very tough. When O1 and 15n20 are used together, it may get a combination of toughness and wear resistance not found in either steel. There is also the possibility of increased edge retention with damascus steels. Two steels that have high edge retention with different compositions, and possibly for different compositional reasons, may have the best of both worlds when used together. A common example is the serration effect given by a softer steel with a hard one. This can be good or bad, depending on the application. Another example is our AEB-L/154CM damascus, one is a steel with very small carbides (AEB-L), and the other has large carbides (154CM). The AEB-L is going to be fine grained and have small carbides, giving it a fine, polished edge, good for certain cuts, while 154CM is convential, meaning it will have some large, bulky carbides, which generally means your knife edge is going to be slightly toothy after some cutting, even if you get a fine polish in the first place, which is good for many different cuts than those good for a polished edge. Together, you may get some of the best properties of both. We plan on doing testing on this, either with a CATRA machine or another method, though it might be difficult to show that there is an increase in performance with general testing methods. Another interesting thing about high-alloy double high carbon damascus is that the steels respond to heat treatment better after being forge welded together into damascus, meaning they get harder. This shows that there is some reduction of the carbide size, and more evenly distributed carbides, after the forging.
We are also considering providing san-mai material such as stainless laminated CPM-M4 to give some stain resistance and ease of finishing to CPM-M4. In addition to the fine/coarse combinations of AEB-L/154CM, 3V/154CM, etc. we also make coarse/coarse: D2/154CM or fine/fine: AEB-L/CPM-154 and 3V/CPM-154. In double high carbon mixes, we are limited to steels with high nickel in carbon steels (15N20), or high molybdenum in stainless steels (BG42, 154CM/ATS-34, CPM-154) to provide a bright layer for contrast. Those stainless mixes containing high molybdenum such as 154CM are not as easy to etch as those with 302, and require etching with muriatic (swimming pool acid or HCl) or sulfuric acid rather than Ferric Chloride. These high performance mixes are also limited to certain patterns...."
