A method for determining the crystallization temperature in studying internal friction behaviors of bulk metallic glasses

As well known, internal friction (Q− 1) is one of useful resorts for investigating the mechanical relaxation behaviors of bulk metallic glasses (BMGs). However, so far it has been controversial on ascertaining the authentic position of crystallization temperature (Tx) when the peak arises on Q− 1-T heating curve of BMGs. Based on the isochronous measurement results of internal friction and resistivity (ρ) on a series of BMGs, a novel method for determining Tx of BMGs was proposed. By differentiating the curve of Q− 1-T with respect to temperature to obtain dQ− 1/dT-T curve, the inflexion temperature at the left side of the Q− 1-T peak can easily be determined. It is interesting to find that, for all the investigated BMGs in this paper, this inflexion temperature (the peak position of the dQ− 1/dT-T curve) is in correspondence with the Tx obtained from ρ-T curve (ρ is very sensitive to crystallization), with the temperature error of ± 1.5 K. These results suggest that in studying the internal friction behaviors of BMGs, the crystallization temperature can be determined with the inflexion temperature of the Q− 1-T curve, and the position of Tx for BMGs locates at the left side of the Q− 1-T peak, rather than at the Q− 1-T peak temperature or others as pointed in some references.