The Solvus Curve for Guinier–Preston Zones in Al–Zn Alloys: A Diffuse X-Ray Study

A diffuse X-ray scattering study has been carried out on two aluminium–zinc alloys, one containing 15 wt.-% zinc and the other 25 wt.-%. Both were examined after water-quenching and ageing for different times at different temperatures. The results support a proposal made by Lasek (Physica Status Solidi, 1964, 5, K117) regarding the solvus curve for Guinier–Preston zones in aluminium–zinc alloys. The curve by Borelius (J. Metals, 1951, 3, 477) appears to be a lower limit for the transformation (after prolonged ageing) of completely coherent Guinier–Preston zones to partially coherent zones.