Alloy formation occurs when two or more metals, or a metal and a nonmetal, are combined to enhance properties like strength, corrosion resistance, and conductivity. Alloys are classified as substitutional (atoms of similar size replace each other, e.g., brass) or interstitial (smaller atoms fit between metal atoms, e.g., steel). Common alloys include steel (iron and carbon), bronze (copper and tin), and aluminum alloys (with magnesium or silicon). Alloying alters hardness, malleability, and ther...