CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS

Detalhes bibliográficos
Autor(a) principal: Mathias, Ivan
Data de Publicação: 2015
Tipo de documento: Tese
Idioma: por
Título da fonte: Biblioteca Digital de Teses e Dissertações da UEPG
Texto Completo: http://tede2.uepg.br/jspui/handle/prefix/838
Resumo: In this work two vitreous systems are studied, the lithium disilicate (LS2) and sodiumcalcium-silica with stoichiometry 2Na2O.CaO.3SiO2 (2N1C3S) and the glassceramics formed from these by heat treatment. Several properties were determined for the two systems as a function of crystallized volume fraction, from glass to fully crystallization (100%), highlighting the fracture toughness and the brittle-ductile transition, with the last two determined only for the LS2 glass-ceramic. Hardness and elastic modulus were obtained for the two glass-ceramics and their values increase with the crystallized volume fraction in the glass ceramic, with the exception of hardness of 2N1C3S, which has its maximum for the crystallized volume fraction of 9%. Thermal expansion coefficients were determined and are larger in the LS2 glassy phase and in the 2N1C3S crystalline phase, thereby generating mean residual stresses obtained by Selsing model of -76 MPa for the LS2 (compression in the crystal) and 232 MPa for the 2N1C3S (traction in the crystal). The indentation fracture toughness was also determined for the two systems using the Anstis' and Niihara's models. The results show an increase of indentation fracture toughness with the crystalline volume fraction for LS2 glass-ceramic and also a dependence with indentation load. As for the 2N1C3S glass-ceramic, indentation fracture toughness are reduced at intermediate crystalline fractions, which is attributed to residual stresses arising from the difference between the thermal expansion mismatch between the glass and the crystalline phases. LS2 glass-ceramic flexural strength increases with the crystalline fraction, from 103 ± 3 MPa for the glass to 260 ± 20 MPa for the fully crystallized sample. Without the removal of the crystallization surface layer, this value rises to 290 ± 20 MPa. The increase in flexural strength in the first 20% of the crystallized fraction is more pronounced. As the size of the precipitates was kept constant, this increase can be related only to the increase in the crystallized fraction. The residual stress in the matrix, the critical radius of spontaneous cracking of the crystals and the crack mean free path between the precipitates were considered in the analysis of the increase in flexural strength. The existence of pores in the samples was a factor that limited its resistance. The fracture toughness (KDTIC) a function of the crystallized fraction was determined for LS2 glassceramics using the double torsion technique. It was found that KDTIC increases with the crystallized fraction, from 0.75 MPa.m1/2 for the glass to about 3.50 ± 0.05 MPa.m1/2 for the fully crystallized sample, a significant increase of approximately five times. Several factors were analyzed as possible causes of the increase in KDTIC. The experimental data are better adjusted with a recently proposed model with one adjustable parameter that relates the ratio of the crystal and glass areas to the crystallized volume fraction. The brittle-ductile transition (BDT) of LS2 glass and glass-ceramic samples (39% crystallized volume fraction) were determined for three different strain rates. BDT temperatures were determined for each strain rate.Activation energies of BDT for the glass and glass-ceramic were obtained, which were 5.2 ± 0.2 eV and 7 ± 2 eV. It was found that BDT activation energy in glass resembles the activation energy of the LS2 viscous flow, thus concluding the BDT in LS2 is governed by viscous flow of the glass matrix. Finally, the fact of the activation energy of the glass ceramic be larger than the glass was attributed to the fact that the viscosity of the vitreous matrix is "hindered" by the presence of crystalline precipitates. A viscosity model of a rigid spheres composite was used as an analogy to explain this observation.
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spelling Serbena, Francisco CarlosCPF:6861390915http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782578Z3Soares Júnior, Paulo CésarCPF:96180650900http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4795603Z2Soares, Viviane OliveiraCPF:05525376679http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4775735E7Chinelatto, Adriana Scoton AntônioCPF:13967937801http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4721108U7Szezech Júnior, José DaniloCPF:03264806924http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4733989P1CPF:05155346924http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4130508J6Mathias, Ivan2017-07-21T19:25:45Z2015-05-072017-07-21T19:25:45Z2015-04-01MATHIAS, Ivan. CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS. 2015. 178 f. Tese (Doutorado em Fisica) - UNIVERSIDADE ESTADUAL DE PONTA GROSSA, Ponta Grossa, 2015.http://tede2.uepg.br/jspui/handle/prefix/838In this work two vitreous systems are studied, the lithium disilicate (LS2) and sodiumcalcium-silica with stoichiometry 2Na2O.CaO.3SiO2 (2N1C3S) and the glassceramics formed from these by heat treatment. Several properties were determined for the two systems as a function of crystallized volume fraction, from glass to fully crystallization (100%), highlighting the fracture toughness and the brittle-ductile transition, with the last two determined only for the LS2 glass-ceramic. Hardness and elastic modulus were obtained for the two glass-ceramics and their values increase with the crystallized volume fraction in the glass ceramic, with the exception of hardness of 2N1C3S, which has its maximum for the crystallized volume fraction of 9%. Thermal expansion coefficients were determined and are larger in the LS2 glassy phase and in the 2N1C3S crystalline phase, thereby generating mean residual stresses obtained by Selsing model of -76 MPa for the LS2 (compression in the crystal) and 232 MPa for the 2N1C3S (traction in the crystal). The indentation fracture toughness was also determined for the two systems using the Anstis' and Niihara's models. The results show an increase of indentation fracture toughness with the crystalline volume fraction for LS2 glass-ceramic and also a dependence with indentation load. As for the 2N1C3S glass-ceramic, indentation fracture toughness are reduced at intermediate crystalline fractions, which is attributed to residual stresses arising from the difference between the thermal expansion mismatch between the glass and the crystalline phases. LS2 glass-ceramic flexural strength increases with the crystalline fraction, from 103 ± 3 MPa for the glass to 260 ± 20 MPa for the fully crystallized sample. Without the removal of the crystallization surface layer, this value rises to 290 ± 20 MPa. The increase in flexural strength in the first 20% of the crystallized fraction is more pronounced. As the size of the precipitates was kept constant, this increase can be related only to the increase in the crystallized fraction. The residual stress in the matrix, the critical radius of spontaneous cracking of the crystals and the crack mean free path between the precipitates were considered in the analysis of the increase in flexural strength. The existence of pores in the samples was a factor that limited its resistance. The fracture toughness (KDTIC) a function of the crystallized fraction was determined for LS2 glassceramics using the double torsion technique. It was found that KDTIC increases with the crystallized fraction, from 0.75 MPa.m1/2 for the glass to about 3.50 ± 0.05 MPa.m1/2 for the fully crystallized sample, a significant increase of approximately five times. Several factors were analyzed as possible causes of the increase in KDTIC. The experimental data are better adjusted with a recently proposed model with one adjustable parameter that relates the ratio of the crystal and glass areas to the crystallized volume fraction. The brittle-ductile transition (BDT) of LS2 glass and glass-ceramic samples (39% crystallized volume fraction) were determined for three different strain rates. BDT temperatures were determined for each strain rate.Activation energies of BDT for the glass and glass-ceramic were obtained, which were 5.2 ± 0.2 eV and 7 ± 2 eV. It was found that BDT activation energy in glass resembles the activation energy of the LS2 viscous flow, thus concluding the BDT in LS2 is governed by viscous flow of the glass matrix. Finally, the fact of the activation energy of the glass ceramic be larger than the glass was attributed to the fact that the viscosity of the vitreous matrix is "hindered" by the presence of crystalline precipitates. A viscosity model of a rigid spheres composite was used as an analogy to explain this observation.No presente trabalho são estudados dois sistemas vítreos, o dissilicato de lítio (LS2) e o soda-cal-sílica de estequiometria 2Na2O.CaO.3SiO2 (2N1C3S), bem como os vitrocerâmicos formados a partir destes através de tratamentos térmicos. Diversas propriedades foram determinadas para os dois sistemas em função da fração cristalizada, desde vidro até os 100%, com destaque para a tenacidade à fratura e a transição frágil-dúctil, sendo estas últimas determinadas somente para o LS2. Dureza e módulo de elasticidade foram obtidos para os dois sistemas e seus valores aumentam com a fração volumétrica cristalizada no vitrocerâmico, com exceção da dureza no 2N1C3S, que tem seu máximo para a fração cristalizada de 9%. Os coeficientes de expansão térmica foram determinados e são maiores na fase vítrea do LS2 e na fase cristalina do 2N1C3S, gerando assim tensões residuais médias obtidas pelo modelo de Selsing de -76 MPa para o LS2 (compressiva no cristal) e 232 MPa para o 2N1C3S (trativa no cristal). A tenacidade à fratura por indentação (KC) foi determinada também para os dois sistemas, sendo utilizados os modelos de Anstis e Niihara. Os resultados mostram um aumento com a fração cristalina para o LS2 e também uma dependência com a carga utilizada no teste. Já para o 2N1C3S, os valores de KC sofrem uma redução em frações cristalinas intermediárias, comportamento atribuído às tensões residuais oriundas da diferença entre os coeficientes de expansão térmica e anisotropias elásticas do material. Os ensaios de resistência à flexão mostraram que para o LS2 a resistência aumenta com a fração cristalina, passando de 103 ± 3 MPa para o vidro para 260 ± 20 MPa para a amostra totalmente cristalizada. Se não removermos a camada de cristalização superficial, este valor sobe para 290 ± 20 MPa. O aumento da resistência à flexão nos primeiros 20% da fração cristalizada é mais pronunciado. Como o tamanho dos precipitados foi mantido constante, esse aumento pode ser relacionado apenas ao aumento na fração cristalizada. A tensão residual na matriz, o raio crítico dos cristais para trincamento espontâneo e o livre caminho médio da trinca entre os precipitados foram considerados na análise do aumento da resistência à flexão. A existência de poros nas amostras foi um fator que limitou a sua resistência. Caso amostras sem poros fossem feitas, um aumento em torno de 20 a 30% da resistência seria obtido. A tenacidade à fratura (KDTIC) foi determinada para o LS2 pela técnica de torção dupla em função da fração cristalizada. Foi verificado que KDTIC aumenta com a fração cristalizada, passando de 0,75 MPa.m1/2 para o vidro para cerca de 3,50 ±0,05 MPa.m1/2 para a amostra totalmente cristalizada, um aumento significativo de aproximadamente cinco vezes. Diversos fatores foram apontados como possíveis causas do aumento da tenacidade e foi verificado que os fatores considerados de forma isolada não são suficientes para descrever completamente o aumento na tenacidade. Os dados experimentais são melhor ajustados com um modelo de um parâmetro de ajuste recentemente proposto que relaciona a razão entre as áreas dos cristais e do vidro na superfície de fratura com a fração cristalizada. A transição frágil-dúctil (TFD) de amostras vítreas e vitrocerâmica (39% fração cristalizada) de LS2 foram determinadas para três taxas de deformação. Foram determinadas as temperaturas de TFD para cada uma das taxas e foi verificada uma dependência com a taxa de deformação. Foram calculadas as energias de ativação para a TFD no vidro e vitrocerâmico, sendo elas de 5,2 ± 0,2 eV e 7 ± 2 eV. Verificou-se que a energia de ativação da TFD no vidro se assemelha a energia de ativação do escoamento viscoso do LS2, concluindo assim que a TFD no LS2 é governada pelo escoamento viscoso da matriz vítrea. Por fim, o fato da energia de ativação do vitrocerâmico ser maior que do vidro foi atribuída ao fato de que a viscosidade da matriz vítrea seria "dificultada" pela presença dos precipitados cristalinos. Um modelo de viscosidade de um compósito com esferas rígidas foi utilizado como analogia para explicar essa observação.Made available in DSpace on 2017-07-21T19:25:45Z (GMT). No. of bitstreams: 1 Ivan Mathias.pdf: 11996423 bytes, checksum: f3bdcfad9b494e72052f6a36c4a749d4 (MD5) Previous issue date: 2015-04-01Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paranáapplication/pdfporUNIVERSIDADE ESTADUAL DE PONTA GROSSAPrograma de Pós-Graduação em CiênciasUEPGBRFisicavidrosvitrocerâmicasvidro dissilicato de lítiovidro soda-calsílicatransição frágil-dúctiltenacidade à fraturaglassesglass-ceramicslithium disilicate glasssoda-lime-silica glassbrittle-ductile transitionfracture toughnessCNPQ::CIENCIAS EXATAS E DA TERRA::FISICACARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOSinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/openAccessreponame:Biblioteca Digital de Teses e Dissertações da UEPGinstname:Universidade Estadual de Ponta Grossa (UEPG)instacron:UEPGORIGINALIvan Mathias.pdfapplication/pdf11996423http://tede2.uepg.br/jspui/bitstream/prefix/838/1/Ivan%20Mathias.pdff3bdcfad9b494e72052f6a36c4a749d4MD51prefix/8382017-07-21 16:25:45.786oai:tede2.uepg.br:prefix/838Biblioteca Digital de Teses e Dissertaçõeshttps://tede2.uepg.br/jspui/PUBhttp://tede2.uepg.br/oai/requestbicen@uepg.br||mv_fidelis@yahoo.com.bropendoar:2017-07-21T19:25:45Biblioteca Digital de Teses e Dissertações da UEPG - Universidade Estadual de Ponta Grossa (UEPG)false
dc.title.por.fl_str_mv CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS
title CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS
spellingShingle CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS
Mathias, Ivan
vidros
vitrocerâmicas
vidro dissilicato de lítio
vidro soda-calsílica
transição frágil-dúctil
tenacidade à fratura
glasses
glass-ceramics
lithium disilicate glass
soda-lime-silica glass
brittle-ductile transition
fracture toughness
CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
title_short CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS
title_full CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS
title_fullStr CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS
title_full_unstemmed CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS
title_sort CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS
author Mathias, Ivan
author_facet Mathias, Ivan
author_role author
dc.contributor.advisor1.fl_str_mv Serbena, Francisco Carlos
dc.contributor.advisor1ID.fl_str_mv CPF:6861390915
dc.contributor.advisor1Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782578Z3
dc.contributor.advisor-co1.fl_str_mv Soares Júnior, Paulo César
dc.contributor.advisor-co1ID.fl_str_mv CPF:96180650900
dc.contributor.advisor-co1Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4795603Z2
dc.contributor.referee1.fl_str_mv Soares, Viviane Oliveira
dc.contributor.referee1ID.fl_str_mv CPF:05525376679
dc.contributor.referee1Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4775735E7
dc.contributor.referee2.fl_str_mv Chinelatto, Adriana Scoton Antônio
dc.contributor.referee2ID.fl_str_mv CPF:13967937801
dc.contributor.referee2Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4721108U7
dc.contributor.referee3.fl_str_mv Szezech Júnior, José Danilo
dc.contributor.referee3ID.fl_str_mv CPF:03264806924
dc.contributor.referee3Lattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4733989P1
dc.contributor.authorID.fl_str_mv CPF:05155346924
dc.contributor.authorLattes.fl_str_mv http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4130508J6
dc.contributor.author.fl_str_mv Mathias, Ivan
contributor_str_mv Serbena, Francisco Carlos
Soares Júnior, Paulo César
Soares, Viviane Oliveira
Chinelatto, Adriana Scoton Antônio
Szezech Júnior, José Danilo
dc.subject.por.fl_str_mv vidros
vitrocerâmicas
vidro dissilicato de lítio
vidro soda-calsílica
transição frágil-dúctil
tenacidade à fratura
topic vidros
vitrocerâmicas
vidro dissilicato de lítio
vidro soda-calsílica
transição frágil-dúctil
tenacidade à fratura
glasses
glass-ceramics
lithium disilicate glass
soda-lime-silica glass
brittle-ductile transition
fracture toughness
CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
dc.subject.eng.fl_str_mv glasses
glass-ceramics
lithium disilicate glass
soda-lime-silica glass
brittle-ductile transition
fracture toughness
dc.subject.cnpq.fl_str_mv CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
description In this work two vitreous systems are studied, the lithium disilicate (LS2) and sodiumcalcium-silica with stoichiometry 2Na2O.CaO.3SiO2 (2N1C3S) and the glassceramics formed from these by heat treatment. Several properties were determined for the two systems as a function of crystallized volume fraction, from glass to fully crystallization (100%), highlighting the fracture toughness and the brittle-ductile transition, with the last two determined only for the LS2 glass-ceramic. Hardness and elastic modulus were obtained for the two glass-ceramics and their values increase with the crystallized volume fraction in the glass ceramic, with the exception of hardness of 2N1C3S, which has its maximum for the crystallized volume fraction of 9%. Thermal expansion coefficients were determined and are larger in the LS2 glassy phase and in the 2N1C3S crystalline phase, thereby generating mean residual stresses obtained by Selsing model of -76 MPa for the LS2 (compression in the crystal) and 232 MPa for the 2N1C3S (traction in the crystal). The indentation fracture toughness was also determined for the two systems using the Anstis' and Niihara's models. The results show an increase of indentation fracture toughness with the crystalline volume fraction for LS2 glass-ceramic and also a dependence with indentation load. As for the 2N1C3S glass-ceramic, indentation fracture toughness are reduced at intermediate crystalline fractions, which is attributed to residual stresses arising from the difference between the thermal expansion mismatch between the glass and the crystalline phases. LS2 glass-ceramic flexural strength increases with the crystalline fraction, from 103 ± 3 MPa for the glass to 260 ± 20 MPa for the fully crystallized sample. Without the removal of the crystallization surface layer, this value rises to 290 ± 20 MPa. The increase in flexural strength in the first 20% of the crystallized fraction is more pronounced. As the size of the precipitates was kept constant, this increase can be related only to the increase in the crystallized fraction. The residual stress in the matrix, the critical radius of spontaneous cracking of the crystals and the crack mean free path between the precipitates were considered in the analysis of the increase in flexural strength. The existence of pores in the samples was a factor that limited its resistance. The fracture toughness (KDTIC) a function of the crystallized fraction was determined for LS2 glassceramics using the double torsion technique. It was found that KDTIC increases with the crystallized fraction, from 0.75 MPa.m1/2 for the glass to about 3.50 ± 0.05 MPa.m1/2 for the fully crystallized sample, a significant increase of approximately five times. Several factors were analyzed as possible causes of the increase in KDTIC. The experimental data are better adjusted with a recently proposed model with one adjustable parameter that relates the ratio of the crystal and glass areas to the crystallized volume fraction. The brittle-ductile transition (BDT) of LS2 glass and glass-ceramic samples (39% crystallized volume fraction) were determined for three different strain rates. BDT temperatures were determined for each strain rate.Activation energies of BDT for the glass and glass-ceramic were obtained, which were 5.2 ± 0.2 eV and 7 ± 2 eV. It was found that BDT activation energy in glass resembles the activation energy of the LS2 viscous flow, thus concluding the BDT in LS2 is governed by viscous flow of the glass matrix. Finally, the fact of the activation energy of the glass ceramic be larger than the glass was attributed to the fact that the viscosity of the vitreous matrix is "hindered" by the presence of crystalline precipitates. A viscosity model of a rigid spheres composite was used as an analogy to explain this observation.
publishDate 2015
dc.date.available.fl_str_mv 2015-05-07
2017-07-21T19:25:45Z
dc.date.issued.fl_str_mv 2015-04-01
dc.date.accessioned.fl_str_mv 2017-07-21T19:25:45Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
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dc.identifier.citation.fl_str_mv MATHIAS, Ivan. CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS. 2015. 178 f. Tese (Doutorado em Fisica) - UNIVERSIDADE ESTADUAL DE PONTA GROSSA, Ponta Grossa, 2015.
dc.identifier.uri.fl_str_mv http://tede2.uepg.br/jspui/handle/prefix/838
identifier_str_mv MATHIAS, Ivan. CARACTERIZAÇÃO MECÂNICA E TRANSIÇÃO FRÁGIL-DÚCTIL EM MATERIAIS VITROCERÂMICOS. 2015. 178 f. Tese (Doutorado em Fisica) - UNIVERSIDADE ESTADUAL DE PONTA GROSSA, Ponta Grossa, 2015.
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dc.publisher.department.fl_str_mv Fisica
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