Study on the Distribution of G.P.Zones in Al–Zn Alloys

Abstract

Small-angle X-ray scattering intensity was measured for several Al-Zn alloys aged for 60ks at various temperatures between 293 and 393K. Scattering intensities were found to obey a scaling rule, when the alloys with the same chemical composition were aged at different temperatures. Under the present aging conditions, G.P.zones had the average radius between 1 and 2nm, and their average nearest neighbor distance among zones lay in the range between 10 and 25nm. Both of the size and the distance among zones were minimized at the aging temperature around 350K in the binary Al-Zn alloys, and they became smaller and shorter with decreasing temperature in the alloys containing by 0.1 at%Mg. The dependence of the inhomogeneous structure containing G. P. zones on the alloy composition and aging temperature could be qualitatively explained in terms of diffusivity of solute atoms and coherency strain around zones. The present study established a universal method for the small-angle scattering intensity analysis to obtain the knowledge on the spatial distribution as well as the volume fraction and the size distribution of G.P.zones.

Electrical resistivity anomaly: A consequence of nanometric particles in a metal matrix

“…Both behaviors are anomalous, the microstructure contribution being smaller when the zone concentration is larger. This response is in accordance with experimental observation, as the GP zones reach a radius ranging between 1 and 2 nm with an interspace between 10 and 25 nm, respectively [22]. The anomaly is greater as the zone concentration is larger, as expected for aging temperatures far apart from the limit of solubility or in the spinodal region [23].…”