Crystallite Formation Within LM105 Bulk Metallic Glass Via Controlled Heat Treatment Cycling With Considerations for Optimal Crucible Material at High Temperatures
Date
2017-02
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Publisher
New York State College of Ceramics at Alfred University. Inamori School of Engineering.
Abstract
Crystallites consisting of Zr, Ti, Cu, and Ni were formed within an amorphous matrix by reheating samples of the glassy metal LM105 to 405°C. The absence of Al in the crystallite formation suggests that this aluminum remained within the amorphous matrix. The sequence of crystallite formation was investigated using standard x-ray diffraction of samples heated to 5 different temperatures in 20°C steps from 365 to 405°C, and for times from 0 to 60 minutes. The glass transition temperature, measured via differential scanning calorimetry in argon atmosphere, was verified to be between 385°C and 405°C using Archimedes density measurements. The optimal material for interfacing with the molten LM105 alloy was also investigated via a superheated interaction study. In this study, samples of polished, fully amorphous, LM105 were placed on alumina, zircon, silicon nitride, silicon carbide, and Syalon 050, 101, 110, and 201 substrates. These were heated to 1250°C at 5°C per minute in a 95/5 Ar-H atmosphere. The samples were then analyzed using a FEI Co., Inc., Quanta 200F environmental SEM with an EDAX Genesis system. Substrate cross sections revealed that zircon underwent the least corrosion in contrast with superheated LM105, implying, that out of the substrates tested, this is most robust for high temperature applications where ceramics interface directly with molten LM105. This includes initial glass forming techniques such as counter-gravity casting.
Description
Thesis completed in partial fulfillment of the requirements for the degree of Master of Science in Glass Science at the Inamori School of Engineering, New York State College of Ceramics at Alfred University
Type
Thesis
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Keywords
Crystallization, Metallic glasses