alloys

An alloy is a uniform mixture of two or more metals (sometimes with a little non-metal too), blended so thoroughly that it behaves as one material with its own distinct properties.

• Stainless steel, made of iron, nickel, chromium, and a touch of carbon, is stronger and more rust-resistant than plain iron alone — exactly the kind of improvement alloying is used for.
• Brass (copper and zinc) and bronze (copper and tin) are older examples, valued for centuries for their strength and workability compared with pure copper.
• Because an alloy is a mixture, not a compound, its ingredients aren't locked into a fixed ratio — engineers can adjust the mix of metals to fine-tune how hard, light, or corrosion-resistant the final alloy turns out.
• Ancient Indian texts describe alloys like bronze being used for far more than tools — even for medicinal purposes, showing how long humans have deliberately engineered mixtures of metals.