TY - JOUR
T1 - In-situ scattering study of a liquid-liquid phase transition in Fe-B-Nb-Y supercooled liquids and its correlation with glass-forming ability
AU - Ge, Jiacheng
AU - He, Haiyan
AU - Zhou, Jing
AU - Lu, Chenyu
AU - Dong, Weixia
AU - Liu, Sinan
AU - Lan, Si
AU - Wu, Zhenduo
AU - Wang, Anding
AU - Wang, Liang
AU - Yu, Cun
AU - Shen, Baolong
AU - Wang, Xun li
N1 - Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/5/30
Y1 - 2019/5/30
N2 - In-situ synchrotron high-energy X-ray diffraction was used to study the kinetics of structure evolution for two Fe-based bulk metallic glasses with different thermophysical behaviors upon heating and isothermal annealing in the supercooled liquid region. It is found that the structure change of (Fe0.72B0.24Nb0.04)97Y3, an average glass former, follows a continuous disordering process before crystallization, while that of (Fe0.72B0.24Nb0.04)95.5Y4.5, a better glass former with an anomalous exothermic peak below the crystallization temperature, is characterized by a reentrant supercooled liquid behavior. A hidden amorphous phase with a configurationally highly-correlated structure is found at a critical temperature of the anomalous exothermic peak for the (Fe0.72B0.24Nb0.04)95.5Y4.5 supercooled liquid, and then it reenters the disordered phase of lower correlation length at a higher temperature. Synchrotron diffraction and the density measurements together illustrate that the liquid-liquid phase transition accompanies with an unusual density change upon isothermal annealing at the anomalous exothermic peak temperature. Our experimental results suggest that a liquid-liquid phase transition which occurred at the medium-range length scale plays an important role in stabilizing the (Fe0.72B0.24Nb0.04)95.5Y4.5 supercooled liquid. Possible mechanisms for the observed differences and the relationship with the glass-forming ability are discussed based on the results of the pair distribution function analysis.
AB - In-situ synchrotron high-energy X-ray diffraction was used to study the kinetics of structure evolution for two Fe-based bulk metallic glasses with different thermophysical behaviors upon heating and isothermal annealing in the supercooled liquid region. It is found that the structure change of (Fe0.72B0.24Nb0.04)97Y3, an average glass former, follows a continuous disordering process before crystallization, while that of (Fe0.72B0.24Nb0.04)95.5Y4.5, a better glass former with an anomalous exothermic peak below the crystallization temperature, is characterized by a reentrant supercooled liquid behavior. A hidden amorphous phase with a configurationally highly-correlated structure is found at a critical temperature of the anomalous exothermic peak for the (Fe0.72B0.24Nb0.04)95.5Y4.5 supercooled liquid, and then it reenters the disordered phase of lower correlation length at a higher temperature. Synchrotron diffraction and the density measurements together illustrate that the liquid-liquid phase transition accompanies with an unusual density change upon isothermal annealing at the anomalous exothermic peak temperature. Our experimental results suggest that a liquid-liquid phase transition which occurred at the medium-range length scale plays an important role in stabilizing the (Fe0.72B0.24Nb0.04)95.5Y4.5 supercooled liquid. Possible mechanisms for the observed differences and the relationship with the glass-forming ability are discussed based on the results of the pair distribution function analysis.
KW - Bulk metallic glasses
KW - Crystallization
KW - Glass-forming ability
KW - Liquid-liquid phase transition
KW - Locally favored structures
UR - http://www.scopus.com/inward/record.url?scp=85061621296&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2019.02.114
DO - 10.1016/j.jallcom.2019.02.114
M3 - Article
AN - SCOPUS:85061621296
SN - 0925-8388
VL - 787
SP - 831
EP - 839
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
ER -