Hu, L.N.

Hui, X.D.

Sun, Q.J.

Wang, C.W.

Yue, Yuanzheng

Zhou, Chao

    Aalborg UniversitetDifferent Sub-Tg Relaxation Patterns in Metallic Glasses far from EquilibriumHu, L.N.; Zhou, Chao; Wang, C.W.; Sun, Q.J.; Hui, X.D.; Yue, YuanzhengPublished in:The 24th International Congress on Glass - AbstractsPublication date:2016Document VersionPublisher's PDF, also known as Version of recordLink to publication from Aalborg UniversityCitation for published version (APA):Hu, L. N., Zhou, C., Wang, C. W., Sun, Q. J., Hui, X. D., & Yue, Y. (2016). Different Sub-Tg Relaxation Patternsin Metallic Glasses far from Equilibrium. In The 24th International Congress on Glass - Abstracts (pp. 148).International Commission on Glass (ICG).General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            ? You may not further distribute the material or use it for any profit-making activity or commercial gain            ? You may freely distribute the URL identifying the publication in the public portal ?Take down policyIf you believe that this document breaches copyright please contact us at vbn@aub.aau.dk providing details, and we will remove access tothe work immediately and investigate your claim.Downloaded from vbn.aau.dk on: April 30, 2017 Different Sub-Tg Relaxation Patterns in Metallic Glasses far from Equilibrium  L. N. Hu1, C. Zhou1, C. W. Wang1, Q. J. Sun1, X. D. Hui2, Y. Z. Yue3 1Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China 2State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China 3Department of Chemistry and Bioscience, Aalborg University, DK-9220 Aalborg, Denmark  hulina0850@sina.com   We investigate the sub-Tg relaxation patterns (RPs) in CuZrAl and LaAlNi glass ribbons (GRs) by using the hyperquenching-sub-Tg annealing-calorimetric approach.1-3) Different from the monotonic relaxation pattern observed in rare-earth based metallic GRs, the abnormal three-steplike sub-Tg relaxation pattern has been observed in CuZrAl ternary glasses. It has been found that the presence of this three-steplike sub-Tg RPs of CuZrAl closely relates to the fictive temperature Tf where the supercooled liquids are frozen in during cooling. Only in a certain range of Tf (or cooling rate for fabrication), this thermodynamic anomaly can be observed. Accompanied with this thermodynamic anomaly, we have observed a three-stage evolution of structures with the increase of annealing degree on CuZrAl GRs. It indicates a dramatic change of the MRO clusters around 1.3 Tg upon cooling in supercooled liquids, which is due to the competitions among the MRO clusters composed of different locally ordering configuration. 3,4)  This accords well with the models based on the competitions between the low-temperature and high-temperature clusters used in the terms of the fragile-to-strong (F-S) transition. In order to further clarify the generality and the origin of this remarkable abnormal thermodynamic phenomenon, the sub-Tg relaxation patterns (RPs) was also detected in other Cu-based metallic GRs. It has been found that this abnormal RPs can be observed in binary CuZr and ternary CuZrAl glasses, rather in quaternary CuZrAlNi. It shows that the anomaly of sub-Tg relaxation pattern could not be simply attributed to the large difference in the enthalpy of mixing between different elements in alloys. By using a high-temperature torsional oscillating viscometer, the existence of the liquid-liquid phase transition (LLPT) depicted by anomalous viscosity drop during cooling in superheated liquids is also been observed in CuZr and CuZrAl melts. In accordance with this dynamic anomaly well above the liquidus temperature, the thermodynamic evidence in these alloys has also been detected above Tl. A close link between the abnormal three-steplike sub-Tg relaxation pattern in GRs and the LLPT in their corresponding melts has been discovered. This work helps to better understand the complex structural evolution from superheated to glassy solids approaching Tg.   Fig. 1 Sub-Tg relaxation pattern of the hyperquenched GRs (a) La55Al25Ni20 ; (b) Cu45Zr45Al10. All the Cp curves were obtained at a heating rate of 20 K/min. Ta points to the annealing temperature and t points to the annealing time. The curves G and H in (b) reflect the non-monotonic relaxation pattern of CuZrAl glass ribbons.  1)  L. N. Hu, C. Zhou, C. Z. Zhang. Y. Z. Yue, Thermodynamic Anomaly of the Sub-Tg Relaxation in Hyperquenched Metallic Glasses. J. Chem. Phys. 138 (2013) 174508 2) X. N. Yang, C. Zhou, Q. J Sun, L. N. Hu, J. C. Mauro, C. Z Wang, Y. Z. Yue, Anomalous crystallization as a signature of the fragile-to-strong transition in metallic glass forming liquids, J. Phys. Chem. B, 118 (2014) 10258. 3) C. W. Wang, L. N. Hu, C. Wei, X. Tong, C. Zhou, Q. J. Sun, X. D. Hui, Y. Z. Yue, Sub-Tg relaxation patterns in Cu-based metallic glasses far from equilibrium , J. Chem. Phys. 141 (2014) 164507 4) C. Zhou , L. N. Hu, Q. J. Sun, C. Z. Zhang, Y. Z. Yue, Fragile-to-strong transition in Cu-based metallic alloys, J. Chem. Phys. 142 (2015) 064508 

Different Sub-Tg Relaxation Patterns in Metallic Glasses far from Equilibrium

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Different Sub-Tg Relaxation Patterns in Metallic Glasses far from Equilibrium

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