Attempt to depict glass forming ability of bulk metallic glasses using the criterion of the total relaxation time at the glass transition

The relationship between the total relaxation time at the glass transition τTgtot and Glass Forming Ability (GFA) of Bulk Metallic Glasses (BMG) has been discussed. Subsequently τTgtot is applied to estimate the GFA of Zr52.5Al10Ni14.6Cu17.9Ti5 and Zr57Al10Ni12.6Cu15.4Nb5 BMGs. The result indicates that the GFA of the former is greater than that of the latter, which is also demonstrated by the widely accepted criteria of both supercooled liquid region ΔTx and reduced glass transition temperature Trg. That testifies the relaxation time of glass transition (τTgtot) is feasible for depicting GFA of BMGs. As a criterion estimating GFA, τTgtot could be easily obtained in practice, and then the occurrence of this criterion will promote exploring new bulk glassy composition. In addition, when τTgtot and ΔTx are calculated, the characteristic temperatures are determined by a electrical resistivity method besides DSC method. The values obtained from electrical resistivity method agree well with those from DSC method, which proves that the electrical resistivity method is applicable for determining the characteristic temperatures of BMGs.