A convenient method is proposed for the measurement of the characteristic free volumes, viz., the amount of excess free volume annihilation in structural relaxation Vf-srand the amount of new free volume production in glass transition Vf-gtof bulk metallic glasses (BMGs) by thermal dilation (DIL) test. Through the DIL tests, the characteristic free volumes are found to be sensitive to the change of glass forming ability (GFA). The Pd40Cu30Ni10P20BMG has a quite small Vf-sr. For a series of Fe-Cr-Mo-C-B-(Er) BMGs, Fe48Cr15Mo14C15B6Er2with the largest GFA is identified to have the largest Vf-gtand smallest Vf-sr. The correlation between Vf-srand the squares of critical diameters of these iron-based BMGs can be fitted as a negative exponential function with high accuracy.
ASJC Scopus subject areas
- Physics and Astronomy(all)