Grain Size Hardening

• Strength can be related to grain size by the Hall-Petch relationship

• ?=?0+kd-1/2

• ? is the yield stress, ?0 is the friction stress and k is a constant

• High strength requires a small grain size which can be achieved by

  • Fast cooling (i.e lots of nucleation due to high ?T)
  • Addition of grain refining elements (e.g. Ti)
  • Cold work, recovery and recrystallisation

Previous slide

Next slide

Back to first slide

View graphic version