Nanocrystallization of bulk Zr-Cu-Ti metallic glass

The phase transformations during heating of Zr30Cu60T10 bulk metallic glass were studied by differential scanning calorimetry, dilatometry, X-ray diff raction, transmission and high resolution electron microscopy. The crystall ization of bulk metallic glass was found to occur in several stages. Accord ing to X-ray diffraction studies the structure was closely similar to amorp hous structure when the sample was heated to the end of the first DSC sub-p eak (781 K). However, the volume effect of the first stage of transformatio n is 1.6%; it forms about 80% of total volume effect of the crystallization (2%). A change of the shape of the diffraction maxima has been analyzed fo r the cases of structure relaxation and nanocrystalline structure formation . The nanocrystalline structure with very fine,grain size was found to form during first stage of crystallization. The grain size of the nanocrystals was 1-5 nm. (C) 2001 Elsevier Science B.V. All rights reserved.