I think even A sword made of one single carved sharpened diamond in its most perfect impure form would be more brittle and easy to break than some steel alloys.
I think that a sword made of Carbon nanotube and diamond would create the strongest, hardest, most tensile, sharpest sword on the planet. Carbon nanotube and diamond bond with eachtoher quite well can makes a solid hardended material. I think if Damascus steel is able to bond or meld it could further imrove its strength and durability.
Imagine a battle, where all of your knights or samurai, were equipped with this blade. Carbon nanotube would also create the most indestructible plated armor and rimmed shields. Your army would be indestructible. An easy to maintain, deadly light, durable, amazing sword. Can you mix things like silicon and tungesten into the picture? Im not sure if they will bond like the others.
A sword cannot be ridged It has to have some flex or it will shatter from it's own vibrations. The best is layered steel, it gives flex and strength and helps to keep an edge. Some of the materials you mentioned may be strong but there molecular structure do not work well for holding an edge.You would just end up with a club.
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