Abstrakt
The development of microstructure in an Al-Sc-Er-Zr alloy during aging at 600 degrees C was investigated utilizing microhardness measurements, positron annihilation spectroscopy (PAS) and (scanning) transmission electron microscopy ((S)TEM). The results of positron lifetime (LT) spectroscopy and coincidence Doppler broadening (CBD) indicate that Sc atoms segregate at dislocations.
Two major groups of precipitates were observed after 4 h of aging at 600 degrees C, one having the usual Er-rich core, Sc-rich inner shell and Zr rich outer shell structure and the other having a core rich in Sc.