COMPETIÇÃO ENTRE RECUPERAÇÃO E RECRISTALIZAÇÃO DINÂMICA DO AÇO INOXIDÁVEL AUSTENÍTICO ASTM F 138 UTILIZADO EM IMPLANTES ORTOPÉDICOS
COMPETITION BEETWEN DYNAMIC RECUPERATION AND RECRYSTALLIZATION OF ASTM F 138 AUSTENITIC STAINLESS STEEL UTILIZED IN MEDICAL DEVICES
Geronimo, Fabio Henrique C.; Balancin, Oscar
http://dx.doi.org/10.4322/tmm.2013.022
Tecnol. Metal. Mater. Min., vol.10, n2, p.162-169, 2013
Resumo
O aço inoxidável austenítico ASTM F138 é utilizado na fabricação de próteses ortopédicas por forjamento. Neste trabalho determinam-se as curvas de escoamento plástico deste aço por meio de ensaios de torção a quente em ampla faixa de temperaturas e diferentes taxas de deformação. A observação microestrutural em diferentes condições de deformação, em conjunto com a utilização da técnica EBSD (Electron Backscatter Difraction), permite calcular a fração recristalizada e identificar as proporções de contornos de alto e baixo ângulos. Tendo esse aço um nível intermediário de Energia de Falha de Empilhamento (EFE), durante o amaciamento dinâmico ocorre a competição entre os mecanismos de recuperação e de recristalização dinâmicas. Assim, este trabalho tem o intuito de identificar os possíveis mecanismos de amaciamento deste aço, bem como aponta em quais condições se tornam mais atuantes.
Palavras-chave
Torção a quente, Recristalização dinâmica, Aço austenítico, EBSD
Abstract
ASTM F 138 austenitic stainless steel has being used in the manufacture of orthopedical devices by hot forging. In this work, the flow stress curves are determined by hot torsion tests in a wide range of temperatures and strain rates. With the observed microestrutural evolution by optical microscopy in different hot forming conditions in addiction with EBSD (Electron Backscatter Diffraction) techniques it is possible to obtained the recrystallized volume fraction and the misorientation angles of the samples. Due to the intermediate level of stacking fault energy of this material, during the dynamic softening occurs a competition between recrystallization and recovery. The aim of this work is to identify the softening mechanisms in this stainless steel, as well as in which hot work conditions they become more active. Key words: Hot torsion; Dynamic recrystallization; Austenitic stainless steel; EBSD.
Keywords
Hot torsion, Dynamic recrystallization, Austenitic stainless steel, EBSD
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