In-situ Small- and Wide Angle X-ray Scattering at the ELETTRA SAXS Beamline on Al-Zn-Mg Alloys

P. Kenesei¹, Gy. Horváth¹, S. Bernstorff², T. Ungár¹ J. Lendvai¹

¹Department of General Physics, Eötvös University Budapest, H-1518 POB. 32, Hungary

²Sincrotrone ELETTRA, Basovizza, I-34012 Trieste

The high flux focused beam of 16 keV photons at the Small Angle X-Ray Scattering (SAXS) beamline of the ELETTRA synchrotron in Trieste has been used to follow the decomposition of the solid solution state in two different Al base Al-Zn-Mg alloys. The specimens were quenched from 470 or 600 ^oC into room temperature (RT) water in the experimental hutch and have been transferred directly into the sample holder. The SAXS measurements were started within between 60 and 120 s after quenching. The small- and wide angle range scattering and diffraction have been recorded by two gas filled linear position sensitive detectors. The diffraction patterns have been saved in 60 s frames up to time periods ranging from about 30 to 90 min. The SAXS patterns are evaluated for the average size and the volume fractions of the Guinier-Preston (GP) zones. From the shifts of the peak positions of the 111 and 200 Bragg reflections the change of the Mg and Zn content of the solid solution during zone formation is evaluated. The offcentre of the diffuse halo appearing around the fundamental 111 and 200 Bragg reflections enables to conclude about the elastic strains produced by the GP zones.