FORMATION OF NANOCRYSTALS BASED ON DECOMPOSITION IN THE AMORPHOUS ZR41.2TI13.8CU12.5NI10BE22.5 ALLOY

Primary crystallization and decomposition in the bulk amorphous alloy Ar41.2Ti13.8Cu12.5Ni10Be22.5 have been studied by small angle neutron scattering (SANS), transmission electron microscopy (TEM), and differe ntial scanning calorimetry (DSC). SANS data of samples annealed isothe rmally at 623 K exhibit an interference peak centered at q=0.46 nm(-1) after an incubation time of about 100 min. TEM and DSC investigations confirm that the respective periodic variation in the scattering leng th density is due to the formation of nanocrystals embedded in the amo rphous matrix. These observations suggest that during the incubation t ime a chemical decomposition process occurs and the related periodic c omposition fluctuations give rise to the observed periodic arrangement of the nanocrystals. (C) 1996 American Institute of Physics.