Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique

Carbon nanotubes (CNTs) have been studied as potential reinforcement for Metal Matrix Composites (MMC) for improving the mechanical properties. However, dispersion and alignment of CNTs in the matrix has been very difficult due to their tendency to form clusters. In the present investigation, the sy...

Full description

Autores:
Isaza Merino, Cesar Augusto
Tipo de recurso:
Doctoral thesis
Fecha de publicación:
2017
Institución:
Universidad Nacional de Colombia
Repositorio:
Universidad Nacional de Colombia
Idioma:
spa
OAI Identifier:
oai:repositorio.unal.edu.co:unal/62291
Acceso en línea:
https://repositorio.unal.edu.co/handle/unal/62291
http://bdigital.unal.edu.co/61317/
Palabra clave:
62 Ingeniería y operaciones afines / Engineering
Metal Matrix Composites
Carbon Nanotubes
Mechanical Properties
Dispersion and Alignment
Interface and Interphases
Materiales compuestos de matriz metálica
Nanotubos de carbono
Propiedades mecánicas
Dispersión y Alineación
Intercara e Interfaces
Rights
openAccess
License
Atribución-NoComercial 4.0 Internacional
id UNACIONAL2_c3ed43d9c9fb3610b75f6c87f19c99bf
oai_identifier_str oai:repositorio.unal.edu.co:unal/62291
network_acronym_str UNACIONAL2
network_name_str Universidad Nacional de Colombia
repository_id_str
dc.title.spa.fl_str_mv Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique
title Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique
spellingShingle Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique
62 Ingeniería y operaciones afines / Engineering
Metal Matrix Composites
Carbon Nanotubes
Mechanical Properties
Dispersion and Alignment
Interface and Interphases
Materiales compuestos de matriz metálica
Nanotubos de carbono
Propiedades mecánicas
Dispersión y Alineación
Intercara e Interfaces
title_short Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique
title_full Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique
title_fullStr Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique
title_full_unstemmed Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique
title_sort Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique
dc.creator.fl_str_mv Isaza Merino, Cesar Augusto
dc.contributor.author.spa.fl_str_mv Isaza Merino, Cesar Augusto
dc.contributor.spa.fl_str_mv Meza Meza, Juan Manuel
Herrera Ramírez, José Martín
dc.subject.ddc.spa.fl_str_mv 62 Ingeniería y operaciones afines / Engineering
topic 62 Ingeniería y operaciones afines / Engineering
Metal Matrix Composites
Carbon Nanotubes
Mechanical Properties
Dispersion and Alignment
Interface and Interphases
Materiales compuestos de matriz metálica
Nanotubos de carbono
Propiedades mecánicas
Dispersión y Alineación
Intercara e Interfaces
dc.subject.proposal.spa.fl_str_mv Metal Matrix Composites
Carbon Nanotubes
Mechanical Properties
Dispersion and Alignment
Interface and Interphases
Materiales compuestos de matriz metálica
Nanotubos de carbono
Propiedades mecánicas
Dispersión y Alineación
Intercara e Interfaces
description Carbon nanotubes (CNTs) have been studied as potential reinforcement for Metal Matrix Composites (MMC) for improving the mechanical properties. However, dispersion and alignment of CNTs in the matrix has been very difficult due to their tendency to form clusters. In the present investigation, the synthesis of AZ31B magnesium alloy reinforced with multi-walled carbon nanotubes (MWCNTs) have been developed via the “sandwich” technique. This technique produces a material comprised of a metallic matrix and banded structures-layers of MWCNTs, where a polymeric solution is used to disperse and align the MWCNTs. As a result, a better dispersion and alignment of the CNTs in metal matrix composites was obtained. The results obtained showed a good interface between the metal matrix and the MWCNTs, allowing a very good interfacial bonding; thus, the mechanical properties, both at the nano level and in bulk, always showed a good behavior. For this characterization, several microscopy techniques including TEM in situ testing, nanomechanical tests and bulk mechanical tests were used. In the studied zones, interphases between the metal matrix and MWCNTs were not found, phases which could hamper the proper load transference between the matrix and reinforcement. HRTEM analysis allowed to identify the interactions between the metal matrix composites and MWCNTs. In the HRTEM images a semi-coherent and coherent interface between the metal matrix and MWCNTs was found. Additionally, two type of dislocations at the interface were identified: stacked and some dislocations formed to accommodate the Mg crystalline cell in order to produce a semi-coherent surface. No intermediate interphases were found in the studied zones. Notched micro-cantilever in situ TEM tests showed the dependency of the fracture toughness with the MWCNTs added in the magnesium matrix. Suggesting that the fracture toughness of the reinforced zone increases with the MWCNTs percentage added. This changes in the fracture toughness is due to the different strengthening mechanisms such as grain size, dislocation activity and finally to the reinforcements action. On the other hand, microtraction test of the composite clearly shown an increasing in the ultimate strength, stiffness and fracture toughness while the main final failure mechanism of the composite was delamination. Finally, PEO (plasma electrolytic oxidation) coatings were applied on the composite surfaces in order to protect them against corrosion. The results showed a good mechanical and electrochemical behavior of the coating. These results allow thinking in using this kind of composites in medical applications.
publishDate 2017
dc.date.issued.spa.fl_str_mv 2017-12-14
dc.date.accessioned.spa.fl_str_mv 2019-07-02T20:56:12Z
dc.date.available.spa.fl_str_mv 2019-07-02T20:56:12Z
dc.type.spa.fl_str_mv Trabajo de grado - Doctorado
dc.type.driver.spa.fl_str_mv info:eu-repo/semantics/doctoralThesis
dc.type.version.spa.fl_str_mv info:eu-repo/semantics/acceptedVersion
dc.type.coar.spa.fl_str_mv http://purl.org/coar/resource_type/c_db06
dc.type.content.spa.fl_str_mv Text
dc.type.redcol.spa.fl_str_mv http://purl.org/redcol/resource_type/TD
format http://purl.org/coar/resource_type/c_db06
status_str acceptedVersion
dc.identifier.uri.none.fl_str_mv https://repositorio.unal.edu.co/handle/unal/62291
dc.identifier.eprints.spa.fl_str_mv http://bdigital.unal.edu.co/61317/
url https://repositorio.unal.edu.co/handle/unal/62291
http://bdigital.unal.edu.co/61317/
dc.language.iso.spa.fl_str_mv spa
language spa
dc.relation.ispartof.spa.fl_str_mv Universidad Nacional de Colombia Sede Medellín Facultad de Minas Escuela de Ingeniería de Materiales
Escuela de Ingeniería de Materiales
dc.relation.references.spa.fl_str_mv Isaza Merino, Cesar Augusto (2017) Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique. Doctorado thesis, Universidad Nacional de Colombia – Sede Medellín.
dc.rights.spa.fl_str_mv Derechos reservados - Universidad Nacional de Colombia
dc.rights.coar.fl_str_mv http://purl.org/coar/access_right/c_abf2
dc.rights.license.spa.fl_str_mv Atribución-NoComercial 4.0 Internacional
dc.rights.uri.spa.fl_str_mv http://creativecommons.org/licenses/by-nc/4.0/
dc.rights.accessrights.spa.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv Atribución-NoComercial 4.0 Internacional
Derechos reservados - Universidad Nacional de Colombia
http://creativecommons.org/licenses/by-nc/4.0/
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.mimetype.spa.fl_str_mv application/pdf
institution Universidad Nacional de Colombia
bitstream.url.fl_str_mv https://repositorio.unal.edu.co/bitstream/unal/62291/1/8175231_2017.pdf
https://repositorio.unal.edu.co/bitstream/unal/62291/2/8175231_2017.pdf.jpg
bitstream.checksum.fl_str_mv 1950470c6f74b61bcb33a02c0c391019
7834232e7d923a080804d26614c67d97
bitstream.checksumAlgorithm.fl_str_mv MD5
MD5
repository.name.fl_str_mv Repositorio Institucional Universidad Nacional de Colombia
repository.mail.fl_str_mv repositorio_nal@unal.edu.co
_version_ 1814090007689822208
spelling Atribución-NoComercial 4.0 InternacionalDerechos reservados - Universidad Nacional de Colombiahttp://creativecommons.org/licenses/by-nc/4.0/info:eu-repo/semantics/openAccesshttp://purl.org/coar/access_right/c_abf2Meza Meza, Juan ManuelHerrera Ramírez, José MartínIsaza Merino, Cesar Augusto558a2b8d-a8c8-4ab1-b286-bd5fc22f4a4b3002019-07-02T20:56:12Z2019-07-02T20:56:12Z2017-12-14https://repositorio.unal.edu.co/handle/unal/62291http://bdigital.unal.edu.co/61317/Carbon nanotubes (CNTs) have been studied as potential reinforcement for Metal Matrix Composites (MMC) for improving the mechanical properties. However, dispersion and alignment of CNTs in the matrix has been very difficult due to their tendency to form clusters. In the present investigation, the synthesis of AZ31B magnesium alloy reinforced with multi-walled carbon nanotubes (MWCNTs) have been developed via the “sandwich” technique. This technique produces a material comprised of a metallic matrix and banded structures-layers of MWCNTs, where a polymeric solution is used to disperse and align the MWCNTs. As a result, a better dispersion and alignment of the CNTs in metal matrix composites was obtained. The results obtained showed a good interface between the metal matrix and the MWCNTs, allowing a very good interfacial bonding; thus, the mechanical properties, both at the nano level and in bulk, always showed a good behavior. For this characterization, several microscopy techniques including TEM in situ testing, nanomechanical tests and bulk mechanical tests were used. In the studied zones, interphases between the metal matrix and MWCNTs were not found, phases which could hamper the proper load transference between the matrix and reinforcement. HRTEM analysis allowed to identify the interactions between the metal matrix composites and MWCNTs. In the HRTEM images a semi-coherent and coherent interface between the metal matrix and MWCNTs was found. Additionally, two type of dislocations at the interface were identified: stacked and some dislocations formed to accommodate the Mg crystalline cell in order to produce a semi-coherent surface. No intermediate interphases were found in the studied zones. Notched micro-cantilever in situ TEM tests showed the dependency of the fracture toughness with the MWCNTs added in the magnesium matrix. Suggesting that the fracture toughness of the reinforced zone increases with the MWCNTs percentage added. This changes in the fracture toughness is due to the different strengthening mechanisms such as grain size, dislocation activity and finally to the reinforcements action. On the other hand, microtraction test of the composite clearly shown an increasing in the ultimate strength, stiffness and fracture toughness while the main final failure mechanism of the composite was delamination. Finally, PEO (plasma electrolytic oxidation) coatings were applied on the composite surfaces in order to protect them against corrosion. The results showed a good mechanical and electrochemical behavior of the coating. These results allow thinking in using this kind of composites in medical applications.Resumen: Los nanotubos de carbono (CNTs , por sus siglas en inglés) han sido usados como un refuerzo ideal para mejorar las propiedades mecánicas de los materiales compuestos de matriz metálica. Sin embargo, su dispersión y alineación dentro de la matriz es difícil debido a su tendencia a aglomerarse. En la presente investigación, se sintetizó magnesio reforzado con nanotubos de carbono de pared múltiple (MWCNTs, por sus siglas en inglés) por medio de una nueva técnica denomina da tipo sándwich, la cual permite una mejor dispersión y alineación de los nanotubos de carbono en la matriz metálica. Esta técnica produce un material compuesto de matriz metálica por medio de un apilamiento de láminas metálicas y láminas de polímero reforzado con MWCNTs, donde el material polimérico es usado para dispersar y alinear los MWCNTs. Los resultados obtenidos mostraron un muy buen comportamiento de la intercara entre la matriz metálica y los MWCNTs, permitiendo una muy buena unión interfacial; por lo tanto, las propiedades mecánicas, a nivel nano y en volumen, mostraron siempre un buen comportamiento. Para la caracterización se utilizaron varias técnicas de microscopía, pruebas in situ, pruebas nanomecánicas y pruebas mecánicas en volumen. En las zonas de estudio no se hallaron interfases entre la matriz metálica y los MWCNTs, que pudieran dificultar la adecuada transferencia de esfuerzos entre la matriz y los MWCNTs. El análisis HRTEM permitió identificar las interacciones entre los compuestos de matriz metálica y los MWCNT. En las imágenes HRTEM se encontró una interfaz semi-coherente y coherente entre la matriz metálica y los MWCNT. Además, se identificaron dos tipos de dislocaciones en la interfaz: apilamiento y formación de dislocaciones, esta última con el fin producir una superficie semi-coherente. Finalmente, no se encontraron interfases intermedias en las zonas estudiadas. Las pruebas de TEM in situ mostraron la dependencia de la tenacidad a la fractura con los MWCNT añadidos en la matriz de magnesio. Los resultados sugieren que la resistencia a la fractura de la zona reforzada aumenta con el porcentaje de MWCNT añadido. Estos cambios en la resistencia a la fractura se deben a los diferentes mecanismos involucrados, como el tamaño del grano, la actividad de dislocación y finalmente a la acción de los XIV Study of the interface - interphase of a Mg - CNT composite made by an alternative sandwich techniquerefuerzos. Por otro lado, la prueba de micro- tracción del material compuesto mostró claramente un aumento en la resistencia final, la rigidez y la tenacidad a la fractura, mientras que el mecanismo de falla final principal del compuesto fue la de-laminación. Por último y como trabajo adicional, en las superficies de los materiales compuestos se aplicaron recubrimientos de PEO oxidación electrolítica por plasma) para protegerlos contra la corrosión. Los resultados mostraron un buen comportamiento mecánico y electroquímico. Estos resultados permiten pensar en el uso de este tipo de compuestos para aplicaciones médicas.Doctoradoapplication/pdfspaUniversidad Nacional de Colombia Sede Medellín Facultad de Minas Escuela de Ingeniería de MaterialesEscuela de Ingeniería de MaterialesIsaza Merino, Cesar Augusto (2017) Study of the interface - interphase of a Mg-CNT composite made by an alternative sandwich technique. Doctorado thesis, Universidad Nacional de Colombia – Sede Medellín.62 Ingeniería y operaciones afines / EngineeringMetal Matrix CompositesCarbon NanotubesMechanical PropertiesDispersion and AlignmentInterface and InterphasesMateriales compuestos de matriz metálicaNanotubos de carbonoPropiedades mecánicasDispersión y AlineaciónIntercara e InterfacesStudy of the interface - interphase of a Mg-CNT composite made by an alternative sandwich techniqueTrabajo de grado - Doctoradoinfo:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/acceptedVersionhttp://purl.org/coar/resource_type/c_db06Texthttp://purl.org/redcol/resource_type/TDORIGINAL8175231_2017.pdfTesis de Doctorado en Ingeniería - Ciencia y Tecnología de Materialesapplication/pdf9521222https://repositorio.unal.edu.co/bitstream/unal/62291/1/8175231_2017.pdf1950470c6f74b61bcb33a02c0c391019MD51THUMBNAIL8175231_2017.pdf.jpg8175231_2017.pdf.jpgGenerated Thumbnailimage/jpeg5376https://repositorio.unal.edu.co/bitstream/unal/62291/2/8175231_2017.pdf.jpg7834232e7d923a080804d26614c67d97MD52unal/62291oai:repositorio.unal.edu.co:unal/622912024-04-23 23:09:13.483Repositorio Institucional Universidad Nacional de Colombiarepositorio_nal@unal.edu.co