What are the best metals (and alloys) for creating armor and weapons for a fantasy society? I was considering silver, iron, copper, and bronze. Would steel also work?
One of the major technological progressions in human history has been the ability to work increasingly durable metals.
The earliest metal weapons were made from copper, roughly 6000 -7000 years ago. Early copper weapons were frequently produced using a naturally occurring alloy of arsenic and copper. While the arsenic made the copper slightly more brittle, it also helped it hold an edge.
Another alloy that can naturally occur is copper and tin. This produces bronze. Human produced Bronze began somewhere around 4500 years ago.
Iron weapons and armor began to appear sometime around 3000-3500 years ago. This gets a little complicated however. Because Iron was first worked by humans, almost 4000 years ago. The iron being produced wasn’t particularly useful for weapons (or most tools.) So, around 1200BC, the real innovation was the introduction of carbon into the iron smelting process. That’s technically a low-quality steel, so I’m a little uncertain when the exact line between iron and steel weapons occurred, but it’s somewhat academic because steel is just an iron-carbon alloy when you get down to it, and most iron weapons contained some carbon anyway.
The takeaway is, people have been making their weapons out of steel for over three thousand years. Most of the other materials you listed have seen use in warfare, but it depends on when. Bronze overtook and replaced copper, because bronze weapons were vastly superior to copper ones. Iron relegated bronze to history. Forging innovations have meant that, while we’ve been using steel in one form or another for thousands of years, the kinds of steel we’re using have supplanted previous iterations.
These materials are about technological progression. You’re also not going to see serious discrepancies in weapons technology in countries that have had extensive contact with one another. So, if one nation borders another, chances are, radical differences are going to even out fairly quickly. You might see some, specific forging techniques that are kept secret, but you wouldn’t have someone using copper weapons going to war with steel clad knights, when both states have shared a border for centuries.
What you won’t see is silver; it’s too soft for use in weapons and armor. You might see silver ornamentation, or silver ceremonial weapons. However, unless it’s some weird historical footnote, you’re not going to see silver on the battlefield. Now, I know you said, “fantasy,” and yeah, fantasy is one of the times when you’ll see silver used because it has a practical value beyond the normal material. So if silver weapons are the only way you can harm demons, or the undead, in your setting, then you’d see silver being used in weapons, but that’s a very specific case.