Thermal rejuvenation of an aged Au-based metallic glass by fast scanning calorimetry

Journal of Non-Crystalline Solids: X

K. Georgarakis¹  C.M. Meylan²  A.L. Greer³ 

[1] Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK;;Department of Materials Science &School of Aerospace, Transport and Manufacturing, Cranfield University, Cranfield MK43 0AL, UK;

关键词: Fictive temperature;    Metallic glass;    Rejuvenation;    Relaxation;    Ultra-fast scanning calorimetry;    Mechanical properties;   

DOI  :  

来源: DOAJ

【 摘 要 】

A metallic glass (MG) annealed above its glass-transition temperature Tg, and cooled, may show an enthalpy increase ΔH, and other property changes. The extent of this thermal rejuvenation depends on the state of the MG (represented by effective cooling rate Φi) and the post-anneal cooling rate Φc. Previous studies examined effects of (Φc/Φi) up to 102. With a Au-based MG aged for up to 10 years at room temperature, and using fast calorimetry to anneal and then cool at up to 5000 K s−1, we extend (Φc/Φi) to 107. The rejuvenation is limited by anneal temperature or by Φc, when, for all MGs, ΔH/Tg shows a universal approximate scaling with log(Φc/Φi). We detect decoupling of vitrification from α relaxation, and highlight limitations in the use of fictive temperature to characterize glassy states. Rejuvenation of the Au-based MG decreases its elastic modulus and hardness, extending trends reported for other MGs.

【 授权许可】

Unknown