In the present work, rapidly solidified alloys strips with Al-0.24Ti and Al-21Si-0.24Ti(in
wt.%) were prepared by single roller melt-spinning method. The microstructures, phase and
morphology characteristics of the resultant strips were characterized by means of scanning electron
microscopy (SEM),transmission electric microscopy (TEM) and XRD technique. The results show
that the grains have been refined after rapid solidification processing, and the micro-nanocrystalline
grain are formed. The morphology characteristics can be changed. The microstructures of Al-0.24Ti
alloys strip are micro-nanostructure α-Al solid solutions which are similar with granular or nodular,
the corresponding SAD pattern is rings, it presents characteristic of polycrystal; Compared with
equilibrium solidification, the microstructures of hypereutectic Al-Si alloy are changed obviously.
They are composed of primary micro-nanostructure α-Al supersaturated solid solution and
nanocrystal granular (α+Si) eutectic which set in the supersaturated solid solution. The nucleation and
growth of primary silicon are suppressed and primary silicon can not precipitate, meanwhile, α-Al
phase is nucleated which prior to eutectic, therefore the microstructures become into the metastable
state. The mechanism of the formation for microstructures of melt-spinning alloys has also been
discussed.