Metallic Bonding

What an alloy is

• An alloy is a mixture of a metal with one or more other elements (usually another metal, sometimes a non-metal such as carbon)
• Common examples:
  • Steel: iron with a small percentage of carbon
  • Brass: copper and zinc
  • Bronze: copper and tin

Why alloys are harder than the pure metal

• The added element has atoms of a different size from the host metal
• These differently sized atoms disrupt the regular arrangement of the lattice
• The layers can no longer slide smoothly past each other
• The alloy is therefore harder and stronger, with reduced malleability compared with the pure metal