dendrites and an increase of the interdendritic eutectic as the Ni content is increased, approaching 
the eutectic composition (5.7wt% Ni). 
# ANTEELL Or ü - - 
Fig.3: Slowly solidified Al-3wt% Ni alloy. ~~ Fig.4: Rapidly solidified Al-3wt% Ni alloy. 
SEM electron micrograph (composition SEM electron micrograph (composition 
image x150) image x150) 
normally ( 
2m % 
nn mixture - 
EI Yea HL Il - MICO 
Fig.5: Slowly solidified Al-4wt% Ni alloy.  Fig.6: Rapidly solidified Al-4wt% Ni alloy. nz 
SEM electron micrograph (composition SEM electron micrograph (composition 
image x150) image x150) 
Figures 2, 4 and 6 show the microstructure of the same low Ni alloys obtained by applying 
the melt spinning rapid solidification process. The obtained melt spun fibers were 2mm wide, 0.02- 
0.03 mm thick and several meters long. As shown in the SEM micrographs, increasing the cooling 
rate in the range specific to rapid solidification (~10°°C/s) has promoted drastic changes in the 
microstructure, consisting in the disappearance of the two phase structure and the obtention of a 
monophasic structure consisting of a supersaturated a Al solid solution. 
The monophasic structure induced by the rapid solidification process was also ascertained 
by the X-ray diffraction patterns. As seen in Fig. 7b the melt-spun fibers of the Ni richest alloy in 
this group (Al — 4wt % Ni) shows only the face centered cubic a Al solid solution intensity peaks, 
while additional intensity peaks indicating the presence of secondary phase (ALNi intermetallic 
compound) are seen in the diffractogram of the slowly solidified alloy (fig.7a). 
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