• JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
 
  Bookmark and Share
 
 
Doctoral Thesis
DOI
https://doi.org/10.11606/T.97.2022.tde-21062022-092931
Document
Author
Full name
Julio Cesar Pereira dos Santos
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Lorena, 2022
Supervisor
Committee
Coelho, Gilberto Carvalho (President)
Avillez, Roberto Ribeiro de
David, Nicolas
Eleno, Luiz Tadeu Fernandes
Title in Portuguese
Investigação experimental e modelagem termodinâmica do sistema Al-Nb-V
Keywords in Portuguese
Ligas de alta entropia
Método Calphad
Projeção liquidus
Seção isotérmica
Sistema Al-Nb-V
Abstract in Portuguese
Um novo conceito para o desenvolvimento de ligas metálicas vem sendo estudado pela comunidade científica nos últimos anos, trata-se de ligas com elementos multiprincipais, também conhecidas como ligas de alta entropia (HEAs). HEAs constituídas de metais refratários e alumínio se destacam como possíveis ligas para utilização na indústria aeroespacial por apresentaram alta resistência específica. Nesse contexto, torna-se necessário o estudo de sistemas envolvendo metais refratários e o alumínio, como o sistema Al-Nb-V, escolhido como objeto de estudo deste trabalho. Dessa forma, neste trabalho uma seção isotérmica a 1200 °C e uma projeção liquidus foram propostas a partir da caracterização microestrutural (MEV/EDS e DRX) de 23 amostras tratadas termicamente e 56 amostras no estado bruto de fusão, respectivamente. experimental para o sistema Al-Nb-V e realizar a modelagem termodinâmica do mesmo sistema. Os resultados obtidos juntamente com os resultados disponíveis na literatura foram utilizados para alimentar o processo de modelagem termodinâmica do sistema Al-Nb-V pelo método Calphad. Além disso, cálculos ab initio foram realizados para obter as energias de formação dos endemembers derivados dos modelos termodinâmicos adotados e as descrições termodinâmicas dos sistemas binários limítrofes foram adotadas. Ao final, três conjuntos de parâmetros termodinâmicos ternários foram obtidos a partir de três diferentes versões do binário Al-V disponíveis na literatura. A partir do presente trabalho, foi possível publicar três artigos científicos em revistas de seletiva política editorial como a Journal of Phase Equilibria and Diffusion e Calphad Journal.
Title in English
Experimental investigation and thermodynamic modeling of the Al-Nb-V system
Keywords in English
Al-Nb-V system
Calphad method
High-entropy alloys
Isothermal section
Liquidus projection
Abstract in English
A new concept for development of metallic alloys have been studied by the scientific community in recent years, these are alloys composed by multiprincipal elements, also known as High-entropy alloys (HEAs). HEAs composed by high melting points metals and aluminum are possible alloys for using in the aerospace industry since they exhibit high specific resistence. In this context, the study of ternary systems involving Al and refractory metals is necessary. Thus, the Al-Nb-V system was chosen as object of study in the present work. In this way, the isothermal section at 1200 °C and a liquidus projection were proposed based on microstructural characterization (SEM/EDS e XRD) of 23 selected heat-treated alloys and 56 as-cast alloys, respectively. The obtained results and the results previously available in the literature were used in order to feed the thermodynamic modeling procedure of the Al-Nb-V system via Calphad method. Besides that, ab initio calculations were performed in order to obtain the formation energies of endmembers compounds derived from the thermodynamic models and thermodynamic descriptions of the binary systems associated to this ternary were adopted. At the end of the modeling, three sets of ternary thermodynamic parameters were obtained from three different Al-V versions available in the literature. Finally, three scientific articles were published in selective editorial policy journals as Journal of Phase Equilibria and Diffusion e Calphad Journal.
 
WARNING - Viewing this document is conditioned on your acceptance of the following terms of use:
This document is only for private use for research and teaching activities. Reproduction for commercial use is forbidden. This rights cover the whole data about this document as well as its contents. Any uses or copies of this document in whole or in part must include the author's name.
EMT22001_C.pdf (3.10 Mbytes)
Publishing Date
2022-06-21
 
WARNING: Learn what derived works are clicking here.
All rights of the thesis/dissertation are from the authors
CeTI-SC/STI
Digital Library of Theses and Dissertations of USP. Copyright © 2001-2024. All rights reserved.