Al-Zn合金におけるGPゾーンの空間分布に関する研究

抄録

Small-angle X-ray scattering intensity was measured for several Al-Zn alloys aged for 60 ks at various temperatures between 293 and 393 K. 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 ageing conditions, GP zones had the average radius between 1 and 2 nm, and their average nearest neighbour distance among zones lay in the range between 10 and 25 nm. Both of the size and the distance among zones were minimized at the ageing temperature around 350 K 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 imhomogeneous structure containing GP zones on the alloy composition and ageing 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 GP zones.