Structure Maps and Phase Stability in AlTi3 Alloyed with Rare-Earth Elements

Abstract

ABSTRACTRare-earth elements including Y, Er and Sc were added to AlTi3 for stabilizing the Ll2 ordered crystal structure, as predicted by the AB3 structure map. The crystal structure and phase composition in the AlTi3 alloys were studied by electron microprobe analysis, X-ray diffraction and TEM. The solubility limit of the rare-earth elements were determined and correlated with the atomic size factor. The results obtained so far indicate that rare-earth additions are unable to change the crystal structure of AlTi3 from DO19 to Ll2. The inability to stabilize the Ll2 structure demonstrates the need to characterize the structure map domains with a further period-dependent parameter.