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The effect of deformation by nanoindentation on nanocrystallization in amorphous Al 90 Fe 5 Gd 5 was investigated by transmission electron microscopy. Massive precipitation of nanocrystallites is observed within the indents. Under the quasistatic condition used, a temperature rise due to adiabatic heating is likely negligible, confirming that plastic deformation can induce crystallization without a heating effect. The nucleation of nanocrystallites is significantly affected by the strain rate.

Effect of strain rate on the formation of nanocrystallites in an Al-based amorphous alloy during nanoindentationMechanical deformation is expected to be an alternative route for synthesizing nanocrystalline/ amorphous matrix composites. However, it is found that nanocrystalline/amorphous Al 90 Fe 5 Gd 5 composites produced by cold rolling have lower hardness than the as-spun, fully amorphous, alloy. Much smaller pileups are observed around indents in rolled samples than in the as-spun sample. Combining high-resolution transmission electron microscopy with Fourier transform and image filtering, many nanovoids are observed in the shear bands near the boundary with the undeformed matrix.