MICROSTRUCTURAL CHARACTERISTICS AND STABILITY IN A RAPIDLY SOLIDIFIEDAL-FE-NB-SI ALLOY

The microstructure and stability in a rapidly solidified Al-Fe-Nb-Si a lloy were studied by using transmission electron microscopy (TEM) with energy dispersive X-ray spectrometry (EDXS) and X-ray diffraction tec hnique. It is shown that the addition of Nb to Al-Fe-Si alloy may incr ease undercooling of melt, and form the featureless zone structure, th e size of the intercellular phases and the distance between intercellu lars of Al-Fe-Nb-Si alloy are two times smaller than that of AI-Fe-V-S i alloy under the same conditions. Further, the microstructure of the featureless zone has the better thermal stability after annealing at 6 23 K for 24 h.