Precipitate-free zone

Dislocation motion – a condition necessary to cause a material to yield – will require an appreciably lower applied shear stress in PFZs, and consequently these locally weak zones will lead to plastic deformation.

Additionally, low temperatures also lead to a reduction in diffusion rates, minimizing the loss of vacancies and premature growth of grain boundary precipitates.

Therefore, one processing technique to circumvent this is to increase the temperature slightly once a sufficient number of homogeneous nucleation sites have been formed.

[10][5][11] One example would be to introduce Mg in Al alloys[3] Cyclic strengthening (CS), a process wherein a material is mechanically pushed and pulled repeatedly at room temperature, creates fine precipitates that is homogeneously distributed throughout the microstructure.

[12] It has been suggested as an alternative to conventional, precipitate hardened alloys as this process achieves strengthening effects without introducing PFZs.