Experimental Studies of Elasticity, Plastic Flow, and Anelasticity in Metallic-Glass-Forming-Liquids

Author: Harmon, John Shelby, III

Year: 2007

Degree: Dissertation (Ph.D.)

Advisor: Johnson, William Lewis

Committee Members: Johnson, William Lewis; Fultz, Brent T.; Ravichandran, Guruswami; Bhattacharya, Kaushik; Goddard, William A., III

Option: Materials Science

DOI: 10.7907/53AD-3G15

Abstract

A rheological law based on the concept of cooperatively-sheared flow zones is presented, in which the thermodynamic state variable controlling flow is identified to be the isoconfigurational shear modulus of the liquid. The law captures Newtonian as well as non-Newtonian viscosity data for glass-forming metallic liquids over a broad range of fragility. Acoustic measurements on specimens deformed at constant strain rates correlate with the measured steady-state viscosities, and define the relative effects of the “elastic” and “cooperative volume” indices on the liquid fragility. The steady state deformation material properties are evaluated to obtain a relationship between the shear modulus and configurational enthalpy. Furthermore, the material properties are evaluated through steady state in an effort to probe the relaxation mechanisms governing flow.

Files

• 01_Title.pdf (application/pdf)
• 02_Acknowledgments.pdf (application/pdf)
• 03_Abstract.pdf (application/pdf)
• 04_Table_of_Contents.pdf (application/pdf)
• 05_List_of_Figures.pdf (application/pdf)
• 06_List_of_Tables.pdf (application/pdf)
• 07_Chapter_1.pdf (application/pdf)
• 08_Chapter_2.pdf (application/pdf)
• 09_Chapter_3.pdf (application/pdf)
• 10_Chapter_4.pdf (application/pdf)
• 11_Chapter_5.pdf (application/pdf)
• 12_Chapter_6.pdf (application/pdf)
• 13_Chapter_7.pdf (application/pdf)
• 14_Chapter_8.pdf (application/pdf)