Microstructure characterization of rapidly solidified Al-Fe-Cr-Ce alloy by positron annihilation spectroscopy

Positron annihilation spectroscopy was employed for the microstructure characterization of rapidly solidified Al-3 wt.% Cr-3 wt.% Fe-0.8 wt.% Ce alloy prepared by melt spinning. Results of the positron annihilation study are analyzed within the diffusion trapping model and compared with results of X-ray diffraction, transmission electron microscopy and microhardness measurements. A good consistency among all experimental techniques was obtained. The rapidly solidified alloy exhibits ultra fine grained structure, consisting of cells separated by dislocation walls. Annealed samples showed no significant changes in structure up to 400 degrees C which proves good thermal stability of ultra fine grained structure. Exposure of the sample to temperature of 500 degrees C caused significant changes in the material. (C) 2010 Elsevier B.V. All rights reserved.