Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó

Carbide reinforced metallic alloys potentially improve some important mechanical properties required for the overall use of important engineering materials such as steel and nickel. Nevertheless, improved performance is achieved not only by composition enhancement but also by adequate processing tec...

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Main Author: Fernandes, Maria Roseane de Pontes
Other Authors: Martinelli, Antônio Eduardo
Format: doctoralThesis
Language:por
Published: Universidade Federal do Rio Grande do Norte
Subjects:
Níquel. Carbetos. Granulação. Sinterização e Plasma
Composites. Nickel. Carbides. Granulation. Sintering and plasma
CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA
Online Access:https://repositorio.ufrn.br/jspui/handle/123456789/12857
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institution Repositório Institucional
collection RI - UFRN
language por
topic Níquel. Carbetos. Granulação. Sinterização e Plasma
Composites. Nickel. Carbides. Granulation. Sintering and plasma
CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA
spellingShingle Níquel. Carbetos. Granulação. Sinterização e Plasma
Composites. Nickel. Carbides. Granulation. Sintering and plasma
CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA
Fernandes, Maria Roseane de Pontes
Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó
description Carbide reinforced metallic alloys potentially improve some important mechanical properties required for the overall use of important engineering materials such as steel and nickel. Nevertheless, improved performance is achieved not only by composition enhancement but also by adequate processing techniques, such as novel sintering methods in the case of powder metallurgy. The method minimizes energy losses in addition to providing uniform heating during sintering. Thus, the general objective of this study was to evaluate the density, hardness, flexural strength, dilatometric behavior and to analyze the microstructure of metal matrix composites based nickel with addition of carbides of tantalum and / or niobium when sintered in a conventional furnace and Plasma assisted debinding and sintering (PADS). Initially, were defineds best parameters of granulation, screening and mixing procedure. After, mixtures of carbonyl Ni and 5%, 10% and 15 wt.% NbC and TaC were prepared in a Y-type mixer under wet conditions during 60 minutes. The mixtures were then dried and granulated using 1.5 wt. % paraffin diluted in hexane. Granulates were cold pressed under 600 MPa. Paraffin was then removed from the pressed pellets during a pre-sintering process carried out in a tubular furnace at 500 °C during 30 min. The heating rate was 3 ºC/min. The pellets were then sintered using either a plasma assisted reactor or a conventional resistive tubular furnace. For both methods, the heating rate was set to 8 ºC/min up to 1150 °C. The holding time was 60 minutes. The microstructure of the sintered samples was evaluated by SEM. Brinell hardness tests were also carried out. The results revealed that higher density and higher hardness values were observed in the plasma-assisted sintered samples. Hardness increased with the concentration of carbides in the Ni-matrix. The flexural strength also increased by adding the carbides. The decline was larger for the sample with addition of 5% 5% TaC and NbC. In general, compositions containing added carbide 10% showed less porous and more uniform distribution of carbides in the nickel matrix microstructural appearance. Thus, both added carbide and plasma sintering improved density, hardness, flexural strength and microstructural appearance of the composites
author2 Martinelli, Antônio Eduardo
author_facet Martinelli, Antônio Eduardo
Fernandes, Maria Roseane de Pontes
format doctoralThesis
author Fernandes, Maria Roseane de Pontes
author_sort Fernandes, Maria Roseane de Pontes
title Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó
title_short Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó
title_full Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó
title_fullStr Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó
title_full_unstemmed Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó
title_sort compósitos de matriz metálica à base níquel com adição de tac e nbc produzidos via metalurgia do pó
publisher Universidade Federal do Rio Grande do Norte
publishDate 2014
url https://repositorio.ufrn.br/jspui/handle/123456789/12857
work_keys_str_mv AT fernandesmariaroseanedepontes compositosdematrizmetalicaabaseniquelcomadicaodetacenbcproduzidosviametalurgiadopo
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spelling ri-123456789-128572019-01-29T21:28:14Z Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó Fernandes, Maria Roseane de Pontes Martinelli, Antônio Eduardo http://lattes.cnpq.br/6135213219185858 http://lattes.cnpq.br/0022988322449627 Binder, Cristiano http://lattes.cnpq.br/0692818548181755 Hammes, Gisele http://lattes.cnpq.br/0519568387165451 Nascimento, Rubens Maribondo do http://lattes.cnpq.br/8671649752936793 Gomes, Uilame Umbelino http://lattes.cnpq.br/9858094266525225 Níquel. Carbetos. Granulação. Sinterização e Plasma Composites. Nickel. Carbides. Granulation. Sintering and plasma CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA Carbide reinforced metallic alloys potentially improve some important mechanical properties required for the overall use of important engineering materials such as steel and nickel. Nevertheless, improved performance is achieved not only by composition enhancement but also by adequate processing techniques, such as novel sintering methods in the case of powder metallurgy. The method minimizes energy losses in addition to providing uniform heating during sintering. Thus, the general objective of this study was to evaluate the density, hardness, flexural strength, dilatometric behavior and to analyze the microstructure of metal matrix composites based nickel with addition of carbides of tantalum and / or niobium when sintered in a conventional furnace and Plasma assisted debinding and sintering (PADS). Initially, were defineds best parameters of granulation, screening and mixing procedure. After, mixtures of carbonyl Ni and 5%, 10% and 15 wt.% NbC and TaC were prepared in a Y-type mixer under wet conditions during 60 minutes. The mixtures were then dried and granulated using 1.5 wt. % paraffin diluted in hexane. Granulates were cold pressed under 600 MPa. Paraffin was then removed from the pressed pellets during a pre-sintering process carried out in a tubular furnace at 500 °C during 30 min. The heating rate was 3 ºC/min. The pellets were then sintered using either a plasma assisted reactor or a conventional resistive tubular furnace. For both methods, the heating rate was set to 8 ºC/min up to 1150 °C. The holding time was 60 minutes. The microstructure of the sintered samples was evaluated by SEM. Brinell hardness tests were also carried out. The results revealed that higher density and higher hardness values were observed in the plasma-assisted sintered samples. Hardness increased with the concentration of carbides in the Ni-matrix. The flexural strength also increased by adding the carbides. The decline was larger for the sample with addition of 5% 5% TaC and NbC. In general, compositions containing added carbide 10% showed less porous and more uniform distribution of carbides in the nickel matrix microstructural appearance. Thus, both added carbide and plasma sintering improved density, hardness, flexural strength and microstructural appearance of the composites Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Ligas metálicas reforçadas por carbetos melhoram potencialmente algumas propriedades mecânicas necessárias para a utilização de importantes materiais de engenharia, tais como o aço e o níquel. No entanto, o desempenho é conseguido não apenas pela melhoria de composição, mas também por técnicas de processamento adequadas, tais como, novos métodos de sinterização, no caso da metalurgia do pó. Desta forma, o objetivo do presente trabalho foi avaliar a dureza, resistência à flexão, comportamento dilatométrico e analisar a microestrutura de compósitos de matriz metálica base níquel com adição de carbetos de tântalo e/ou nióbio quando sinterizados em forno tubular convencional e Plasma assisted debinding sintering (PADS). Os carbetos (5%, 10% e 15% em massa) foram misturados ao pó de níquel carbonila via úmido com auxílio do misturador Y adaptado durante 1h. Após secagem, as misturas foram submetidas ao processo denominado de granulação em tambor. Utilizou-se 1,5% de parafina (% massa) diluída em hexano. Os pós granulados foram compactados a frio utilizando pressão de 600 MPa. Antes da sinterização a uma taxa de 8 ºC/min com patamar 1h na temperatura de 1150ºC tanto em forno tubular quanto em reator PADS, as amostras foram pré-sinterizadas em forno tubular para extração da parafina a uma taxa de 3 ºC/min com patamar 30 min em 500 °C. A dureza avaliada foi a Brinell e a análise microestrutural por MEV. Os resultados mostraram que as amostras sinterizadas assistidas por plasma apresentaram dureza superior àquelas sinterizadas em forno convencional. As imagens por MEV comprovaram esses maiores valores de durezas, uma vez que a matriz apresentou-se mais densificada. Com relação à adição dos carbetos, a dureza aumentou com o aumento da concentração dos mesmos. A resistência à flexão também aumentou ao adicionar os carbetos. A retração foi maior para a amostra com adição de 5% de TaC e 5% NbC. De maneira geral, as composições com adição de 10% de carbetos apresentaram um aspecto microestrutural menos poroso e com uma distribuição mais uniforme dos mesmos na matriz de níquel. Assim, tanto a adição de carbetos quanto a sinterização com auxílio do plasma melhoraram a dureza e o aspecto microestrutural dos compósitos 2014-12-17T14:07:20Z 2014-09-18 2014-12-17T14:07:20Z 2014-01-24 doctoralThesis FERNANDES, Maria Roseane de Pontes. Compósitos de matriz metálica à base níquel com adição de TaC e NbC produzidos via metalurgia do pó. 2014. 124 f. Tese (Doutorado em Processamento de Materiais a partir do Pó; Polímeros e Compósitos; Processamento de Materiais a part) - Universidade Federal do Rio Grande do Norte, Natal, 2014. https://repositorio.ufrn.br/jspui/handle/123456789/12857 por Acesso Aberto application/pdf application/pdf Universidade Federal do Rio Grande do Norte BR UFRN Programa de Pós-Graduação em Ciência e Engenharia de Materiais Processamento de Materiais a partir do Pó; Polímeros e Compósitos; Processamento de Materiais a part

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