THE DEVITRIFICATION OF AL-Y-FE AMORPHOUS-ALLOYS

Amorphous Al-Y-Fe alloys has been produced via rapid solidification (m elt-spinning) processing. Melt-spun ribbons (MSR) of selected Al-Y-Fe compositions were characterized by differential scanning calorimetery, scanning electron microscopy, X-ray diffraction and transmission elec tron microscopy, The Al88Y7Fe5 as-solidified MSR exhibits a microstruc ture that is predominately amorphous with a sparse distribution of lar ge micrometer size intermetallic phase crystals Thermal cycling of the as-solidified MSR showed an exothermic signal on first heating at aro und 280 degrees C for the Al88Y7Fe5 alloy. The first exothermicreactio n has been determined to be the formation of nanocrystalline aluminum. Further heating resulted in crystallization of the remaining amorphou s material. Isothermal annealing treatments below the continuous heati ng crystallization reactions alter the reactions observed upon reheati ng. The relationship between the formation of amorphous material, the reported observance of a glass transition in the Al-Y-Fe alloys and po ssible impurity effects are examined to evaluate the overall thermal s tability of Al-rich amorphous alloys.