Comparative studies of crystallization of a bulk Zr–Al–Ti–Cu–Ni amorphous alloy

The recrystallization and associated nanoindentation behavior of a Zr–10Al–5Ti–17.9Cu–14.6Ni (at.%) bulk amorphous alloy was investigated using in situ transmission electron microscopy and high-temperature nanoindentation. The onset of recrystallization occurs around 710 K, with the formation of Zr2Cu, Al3Zr4, and Ni10Zr7. Nanoindentation hardness and elastic modulus were obtained as a function of temperature from 298 to 723 K. The hardness was measured to be ∼7.5 GPa and found unchanged at temperatures below 673 K, but softened rapidly and decreased to 5 GPa at 723 K. These results can be correlated very well with the onset of recrystallization of this alloy at ∼700 K. The present study demonstrates that transmission electron microscopy, hot-stage nanoindentation, and X-ray diffraction are supplementary techniques for the study of glass relaxation and crystallization of metallic glasses.