Crystallization Behavior of Fe_(78)B_(13)Si_9, Fe_(81)B_(13)Si_(3.5)C_2, Fe_(66)Co_(18)B_(15)Si and Fe_(77)Cr_2B_(16)Si_5 Metallic Glasses

摘要

The crystallization behavior of α-Fe in Fe_(78)B_(13)Si_9, Fe_(81)B_(13)Si_(3.5)C_2, Fe_(66)Co_(18)B_(15)Si and Fe_(77)Cr_2B_(16)Si_5 metallic glasses has been investigated under controlled crystallization conditions. Based on the onset temperature for α-Fe crystallization, crystallite size and occupied volume, it was concluded that nucleation is enhanced in the Co-bearing alloy; the C-bearing alloy exhibited an anomalous behavior while in the Cr-bearing alloy the growth of the α-Fe crystallites is strongly inhibited. Nanocrystalline structures were restricted to sizes > 50 nm in the base-, C- and Co-bearing alloys, while crystallite sizes < 10 nm were obtained in the Cr-bearing alloy. By determining the rate of change of the number of nuclei with increasing annealing temperatures, the controlling mechanism, either nucleation enhancement and/or growth inhibition, was clearly outlined.