Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/tmm.00501002
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

ANÁLISE DO COMPORTAMENTO SOB EXTRUSÃO DE PÓS NANOESTRUTURADOS DE LIGAS DE ALUMÍNIO COMO UM PROCESSO TERMICAMENTE ATIVADO

EXTRUSION BEHAVIOUR ANALYSIS OF NANOSTRUCTURED ALUMINIUM POWDER ALLOYS UNDER A THERMALLY ACTIVATED PROCESS BASEMENT

Peres, Maurício Mhirdaui; Fogagnolo, João Batista; Kiminami, Claudio Shynti; Botta Filho, Walter José; Bolfarini, Claudemiro; Jorge Junior, Alberto Moreira

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Resumo

Neste trabalho, a extrusão de pós nanoestruturados é analisada a partir do ponto de vista de mecanismos de deformação ativados termicamente, tais como os que operam normalmente em materiais cristalinos convencionais. Pós nanoestruturados de ligas de alumínio foram conformadas por extrusão a quente em três temperaturas diferentes: 375°C, 400°C e 425°C, com razão de extrusão de 10:1 e velocidades de 1 mm/s, 15 mm/s e 30 mm/s. Os dados resultantes foram analisados utilizando equações típicas do trabalho a quente de materiais convencionais, principalmente a equação de Sellars, e os resultados são comparados com os dados da literatura de materiais convencionais processados por extrusão e torção a quente. Pode ser verificado que a extrusão a quente de materiais nanoestruturados também é um processo termicamente ativado, no qual o mecanismo controlador também é a escalagem ou o movimento severo de discordâncias. As mudanças microestruturais observadas são consistentes com os mecanismos de deformação propostos.

Palavras-chave

Extrusão, Pós, Alumínio, Energia de ativação

Abstract

In this work, the hot extrusion of nanostructured powders is analysed from the point of view of thermally activated deformation mechanisms, such as normally operate in conventional crystalline materials. Nanostructured aluminium powders alloy were deformed by hot extrusion at temperatures of 375°C, 400°C and to 425°C, with extrusion ratio of 10:1 and over the ram speed range of 1 mm/s to 30 mm/s. The resultant data were analyzed by means of typical equations from hot working of conventional materials, mainly the Sellars equation, and the results are compared with the literature data of conventional materials processed by hot extrusion and hot torsion. It is concluded that the hot extrusion of nanostructured materials is a thermally activated process, in which the rate-controlling mechanism is either the climb of edge dislocations or the motion of jogged screw dislocation. The microstructural changes observed are consistent with the proposed deformation mechanisms.

Keywords

Extrusion, Powders, Aluminum, Activation energy

Referências

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