Excluding Mercury and other glassy (Amorphous) metals.
I ain't a metallurgist but I'm thinking that some of the elements used in the various steel alloys, Silica, etc. will change the crystalline lattice structure of the knife's blade structure.
Is this not so?
Are all the added alloy elements included into the basic crystalline lattice structure? Maybe someone can jump in to this discussion of knife steels.
Different elements tend to congregate in different places. Most of the common alloying elements in steels will fit into the regular iron atomic arrangement in a substitutional fashion. The arrangement will largely be the same, but there will be say a chromium atom where an iron atom would normally be. Some elements tend to be found in the carbides. They will form their own unique carbides, like tungsten or vanadium carbide, or they will substitute for iron in iron carbide/cementite. In these cases, they can be considered molecules, but it's not that clear always, particularly if one leaves steels. And just to be a picky SOB, silica is silicon dioxide, SiO2. It's definitely found in steel, as silicon is an element added to deoxidize the molten steel. Again, just being picky. For metals, generally speaking, they are not molecular in nature, but there are exceptions to everything. I'm not certain if carbides are considered molecules or not. The bonds might be metallic in nature. I have not looked into it.
Angus7us, I'm not Stacey, but hopefully he won't mind me taking a stab at your question. Unfortunately, I can't give a very clear cut answer. The elements have various effects on grain size, and generally speaking, all of them tend to slow down grain growth. One of the best is Aluminum. It's added as a deoxidizer to the the steel melt. The oxides it forms are extremely fine, and these small oxide particles slow down grain growth very well. The reason my answer is not so clear cut, is the steel processing has a huge effect on the grain size. Without knowing that, it's not really practical to rank how effective the elements are. They also work in different ways, sometimes with the same element. For instance, chromium dissolved in ferrite will slow the rate of grain growth. Chromium carbide will also slow it down, particularly if the carbides are very small. However, I was recently reading of plain carbon steels with extremely small grain sizes, 2 micron and less. These used iron carbide as a barrier to prevent grain growth, though they were processed at relatively high temperatures. There were no other elements added except a lot of carbon. These had 1.5% carbon (a 10150 steel if you will) or more in some cases.