CORRELATION BETWEEN THE GLASS-FORMING ABILITY AND CHARACTERISTIC FREE VOLUMES OF THE IRON BASE BULK METALLIC GLASSES
HU Qiang1), ZENG Xierong2,3), QIAN Haixia2,3), XIE Shenghui2,3), SHENG Hongchao2,3)
1) School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072
2) College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060
3) Shenzhen Key Laboratory of Special Functional Materials, Shenzhen 518060
Cite this article:
HU Qiang ZENG Xierong QIAN Haixia XIE Shenghui SHENG Hongchao. CORRELATION BETWEEN THE GLASS-FORMING ABILITY AND CHARACTERISTIC FREE VOLUMES OF THE IRON BASE BULK METALLIC GLASSES. Acta Metall Sin, 2012, 48(11): 1329-1334.
Many researches have demonstrated that the free volume have a great effect on the properties of bulk metallic glasses (BMGs). For different BMGs, however, quantitative measurement of free volumes and analysis of properties of BMGs using the measurement results are still difficult. In this work, the two types of characteristic free volumes, the free volume released in structural relaxation, ΔVf-sr and the free volume generated in glass transition, ΔVf-gt are given from the Δ(dV(T)/V0) curve, where the Δ(dV(T)/V0) is the thermal expansion difference between amorphous and crystalline samples measured by a cyclic thermal dilation test. In a series of Fe-(Er)-Cr-Mo-C-B BMGs, it is found that the BMG with the largest critical diameter (Dc) has also the largest ΔVf-gt, and Dc increases sensitively with the decrease of ΔVf-sr. More impressively, Dc2 or Dc can be fitted with high regression coefficient of 0.998 by a negative exponential function of ΔVf-sr. Hence, the characteristic free volume has a sensitive and close correlation with the glass forming ability of BMGs.
