• 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
 
 
Master's Dissertation
DOI
https://doi.org/10.11606/D.18.2012.tde-17072012-111457
Document
Author
Full name
Rogério Varavallo
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2012
Supervisor
Committee
Bose Filho, Waldek Wladimir (President)
Nunes, Carlos Ângelo
Pinto, Haroldo Cavalcanti
Title in Portuguese
Avaliação da resistência à fadiga em alta temperatura da superliga MAR-M247(Nb)
Keywords in Portuguese
Nucleação de trinca por fadiga
Oxidação
Superligas de Ni
Abstract in Portuguese
Este projeto faz parte de uma Rede Interdisciplinar de Pesquisa em Superligas no Brasil (Projeto Pró-Engenharias - CAPES), que tem como objetivo o desenvolvimento técnico e científico do Brasil nesta classe de materiais. A rede é composta por especialistas de estabelecida competência em assuntos fundamentais para o desenvolvimento de materiais estruturais, tais como: fusão em vácuo, solidificação direcional, relações orientação-propriedade, tratamentos térmicos, fluência, fadiga em alta temperatura, oxidação e corrosão a quente. Assim, na parte que compete a este pesquisador, foram estudadas as propriedades de fadiga em altas temperaturas da liga MAR-M247 e de uma nova liga, a liga MAR-M247 modificada pela substituição do Ta pelo Nb, e sendo doravante denominada MAR-M247(Nb). Foram desenvolvidos estudos correlacionando parâmetros intrínsecos do material, como composição química e microestrutura adicionalmente a parâmetros extrínsecos, tais como: temperatura, estudo de oxidação, propriedades de fadiga, ensaios de tração em temperatura ambiente, 250, 500, 700, 800, 900 e 1000ºC, conforme as normas AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) E 8M-00 e ASTM E 21-00. Em relação aos ensaios de fadiga foram realizados ensaios de nucleação de trincas , conforme a norma ASTM E466-07 e os resultados foram apresentados na forma de curvas S-N e analisados estatisticamente segunda a norma ASTM E739-10. Para auxiliar na definição dos micromecanismos de fadiga, as superfícies de fratura foram analisadas utilizando o microscópio eletrônico de varredura (MEV) e microscópio ótico estereoscópico (MO). Foi realizado ensaio de oxidação para verificar a susceptibilidade a oxidação das ligas, sendo este um dos fatores que afetam a vida em fadiga em alta temperatura.
Title in English
Evaluation of fatigue strength at high temperature superalloy MAR-M247 (Nb)
Keywords in English
Fatigue crack nucleation
Ni superalloys
Oxidation
Abstract in English
This project is part of an interdisciplinary network of Research in Super League in Brazil (Project Pro-Engineering - CAPES), which aims to technical and scientific development of Brazil in this class of materials. The network is composed of experts of established competence in matters fundamental to the development of structural materials, such as: vacuum melting, directional solidification, relationships property-oriented, heat treatment, creep, fatigue in high temperature oxidation and hot corrosion. Thus, at the racing this researcher, were studied the fatigue properties at high temperatures MAR-M247 alloy and a new league, which in reality is the MAR-M247 alloy modified by replacing the Ta by Nb, and being hereinafter referred to as MAR-M247 (Nb). Were designed studies correlating parameters intrinsic material, such as chemical composition and microstructure, with extrinsic parameters such as: temperature and type of loading, with the properties fatigue. Thus, tensile tests at room temperature environment, 250, 500, 700 and 900ºC, and tests for compression at temperatures of 700 and 900ºC were performed to determine the elastic behavior and elastoplastic material, according to the ASTM E-8M 00, ASTM E 21-00 and ASTM E209-00. Were also conducted testing of fatigue crack nucleation, as ASTM E466-07. The results were presented at form of SN curves and statistically analyzed the second ASTM E739-10. To assist in the definition of micromechanics of fatigue, the fracture surfaces were examined in a scanning electron microscope (SEM) and stereoscopic optical microscope (OM). Was oxidation test performed to check susceptibility to oxidation of the alloy, which is the factor affecting the fatigue life.
 
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.
RogerioVaravallo.pdf (20.14 Mbytes)
Publishing Date
2012-07-24
 
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.