Estudo da cinÃtica de recristalizaÃÃo da liga de alumÃnio AA 8011 na condiÃÃo H18

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

The AA 8011 alloy is one of the most versatile commercial aluminum alloys. The diversity of its applications depends not only on its chemical composition, but, mainly, on the microstructures transformations that it comes to suffer. In that context, the study of the recrystallization kinetics assumes an important role for facilitating the control of the workhardened state in function of the time of treatment. The objective of this work is to determine the kinetic of recrystallization for each considered property and to study its mechanisms. For so much, they were accomplished, preliminary, dynamic analyses were made in DSC for determination of the temperature of recrystallization of the hardened alloy for each analyzed composition. Soon after, different samples were annealed in temperatures close to the pick of the DSC curves in times that varied from 5 to 180 minutes. After treated, the samples were submitted to mechanical tests (hardness measurements and stress-strain) for lifting of the Properties versus Time of Treatment curves. The values of the properties were related to the of the fraction transformed for determination of the kinetic of recrystallization. For the characterization of the process and its mechanisms, analyses were accomplished in x-ray, optical microscopy and transmission electron microscopy â TEM. The results showed that the equation of the recrystallized fraction follows the empiric law of the formation of Jonhson- Mehl-Avrami for any considered property, as well as, the icrostructural modifications that it happen, being excluded the recrystallization, they are current of the spinodal decomposition and it influence the plasticity of the material significantly. It issues that the conclusion that the recrystallization kinetics has a anisotropical behavior, in which the longitudinal direction express itself differently of the traverse one, and anomalous in what says respect to the evolution of the properties in the domains elastic and plastic

ASSUNTO(S)

ligas de alumÃnio de alta formabilidade ligas de alumÃnio metaestÃveis engenharia mecanica solidificaÃÃo em caster cinÃtica de recristalizaÃÃo decomposiÃÃo em ligas de alumÃnio recristalizaÃÃo

ACESSO AO ARTIGO

Documentos Relacionados