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Dilation Curve Analysis, Cooling Curve Analysis, Phase transformations, Dilatometry, Calorimetry

Kamyabi Gol, Ata Ollah

Supervisor and department: Mendez, Patricio Chemical and Materials Engineering

Examining committee member and department: Bhadeshia, Harry Materials Engineering Chen, Weixing Chemical and Materials Engineering Rajendran, Arvind Chemical and Materials Engineering Li, Leijun Chemical and Materials Engineering

Department: Department of Chemical and Materials Engineering

Specialization: Materials Engineering Welding

Date accepted: 2015-08-24T09:26:50Z

Graduation date: 2015-11

Degree: Doctor of Philosophy

Degree level: Doctoral

Abstract: Dilatometry and calorimetry are well-established techniques, and have been used successfully for decades; however, they are seldom used to quantify the progress of a transformation. Most often, these techniques are used to detect start and finish of transformations. When used quantitatively, current analysis of dilation data does not account for the different changes in density for the multiple transformed phases. Similarly, quantitative calorimetric analysis does not account for different rates of enthalpy release for different transformed phases.The technique proposed for both dilatometry and calorimetry consists on posing a differential equation based on dilation or temperature data generated under controlled experimental conditions. When integrated, this equation extracts phase fraction evolution from the experimental data. Like all differential equations, the equation posed involves coefficients and integration constants. The work presented differs from other similar work in that the coefficients are obtained from calibration before, after, and at transition points for each transformation, with a minimum of need of previously tabulated data.These methods can go beyond any previous approach by quantifying partial transformations and making in-situ measurements of phase fractions in complex simultaneous phase transformations possible. This is possible because of a rigorous framework that reduces the number of unknown parameters to its minimum. The mathematical treatments will be introduced, and applications will be discussed involving precipitation during solidification in aluminum A356 alloy, martensitic transformation in creep-resistant steel, and simultaneous bainitic and martensitic transformations in AISI 4140 steel.

Language: English

DOI: doi:10.7939-R39P2WF1C

Rights: Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.





Autor: Kamyabi Gol, Ata Ollah

Fuente: https://era.library.ualberta.ca/


Introducción



Quantification of phase transformations using calorimetry and dilatometry by Ata Ollah Kamyabi Gol A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Materials Engineering Department of Chemical and Materials Engineering University of Alberta c Ata Ollah Kamyabi Gol, 2015 Abstract Dilatometry and calorimetry are well-established techniques, and have been used successfully for decades; however, they are seldom used to quantify the progress of a transformation.
Most often, these techniques are used to detect start and finish of transformations. When used quantitatively, current analysis of dilation data does not account for the different changes in density for the multiple transformed phases.
Similarly, quantitative calorimetric analysis does not account for different rates of enthalpy release for different transformed phases. The technique proposed for both dilatometry and calorimetry consists on posing a differential equation based on dilation or temperature data generated under controlled experimental conditions.
When integrated, this equation extracts phase fraction evolution from the experimental data.
Like all differential equations, the equation posed involves coefficients and integration constants.
The work presented differs from other similar work in that the coefficients are obtained from calibration before, after, and at transition points for each transformation, with a minimum of need of previously tabulated data. These methods can go beyond any previous approach by quantifying partial transformations and making in-situ measurements of phase fractions in complex simultaneous phase transformations possible.
This is possible because of a rigorous framework that reduces the number of unknown parameters to its minimum.
The mathematical treatments will be introduced, and applications will be discussed involving precipitation during soii lidification in aluminum A356 alloy, martensitic transformat...





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