MEPX
Chapter 3 of 10All chapters
  1. 1Describing a material
  2. 2Structure decides behaviour
  3. 3Metals
  4. 4Ceramics and polymers
  5. 5Composites
  6. 6How materials fail
  7. 7Processing changes properties
  8. 8Choosing a material
  9. 9Modern materials
  10. 10Materials and sustainability

Chapter 3 of 10

Metals

Strong, tough and workable.

Why they behave that way

Metal atoms share a sea of electrons, which is why metals conduct heat and electricity and deform without shattering. That deformation is what makes them formable.

  • Alloying, work hardening and heat treatment all obstruct dislocation movement.
  • Steel is iron plus carbon; stainless adds chromium for a protective oxide layer.

Corrosion

Most metals react with oxygen and water. Aluminium forms a tight oxide skin that protects it; iron forms rust that flakes off and exposes fresh metal, which is why it keeps going.