Shear rate dependence of viscosity and configurational entropy of the Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 metallic glass forming liquid

Autor:	Ralf Busch, Tyler Shaw, Prashant Wadhwa, Christopher Way
Rok vydání:	2007
Předmět:	Materials science Mechanical Engineering Rheometer Configuration entropy Metals and Alloys Thermodynamics Liquidus Apparent viscosity Heat capacity Physics::Fluid Dynamics Shear rate Entropy of fusion Mechanics of Materials Materials Chemistry Newtonian fluid
Zdroj:	Journal of Alloys and Compounds. :88-91
ISSN:	0925-8388
Popis:	In this study the viscosity of Zr 41.2 T 13.8 Cu 12.5 Ni 10.0 Be 22.5 (Vit 1) has been measured as a function of temperature and shear rate above the liquidus temperature, T liq = 1026 K, using a high temperature Couette Rheometer. It has been discovered that there exists a pronounced decrease in viscosity with increasing shear rate. This is contrary to the general belief that metallic systems above the liquidus temperature should show Newtonian behavior. It has also been discovered that this shear rate dependence of the viscosity decreases with increasing temperature and approaches the Newtonian behavior and viscosities of simple monatomic liquids or binary alloys at approximately 1300 K. These results are discussed in terms of configurational entropy, S c , by using the Adam-Gibbs entropy model for viscous flow. It is suggested that a large amount of short-range order still exists above the liquidus temperature. At high shear rates this order is destroyed causing the configurational entropy to increase by a magnitude that is on the order of the entropy of fusion.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8e8b6ef1af87f883ad27cfa6d10760bd https://doi.org/10.1016/j.jallcom.2006.08.116 Zobrazit plný text záznamu Full Text from ScienceDirect