Guinier–Preston zone

A Guinier–Preston zone, or GP-zone, is a fine-scale metallurgical phenomenon, involving early stage precipitation.[1][2]

GP-zones are associated with the phenomenon of age hardening, whereby room-temperature reactions continue to occur within a material through time, resulting in changing physical properties. In particular, this occurs in several aluminium series, such as the 6000 and 7000 series alloys.

Physically, GP zones are extremely fine-scaled (on the order of 3–10 nm in size) solute enriched regions of the material, which offer physical obstructions to the motion of dislocations, above that of the solid-solution strengthening of the solute components. In 7075 aluminium for example,[3] Zn–Mg clusters precede the formation of equilibrium MgZn2 precipitates.

The zone is named after Prof George Dawson Preston who noted the effect (concurrently with Andre Guinier) in 1938.[4]

References

  1. ↑ Guinier-Preston zone evolution in 7075 Aluminium (PDF).
  2. ↑ "A. Guinier - Personal Reminiscences" (PDF).
  3. ↑ "Microstructural Evolution and Age Hardening in Aluminium Alloys: Atom Probe Field-Ion Microscopy and Transmission Electron Microscopy Studies" (PDF).
  4. ↑ https://www.dundee.ac.uk/museum/exhibitions/madetomeasure/scientists/#preston

Further reading

  • G.D Preston, Structure of age-hardening aluminium–copper alloys, Nature 142 (1938) 570, September 24
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