On the Precipitation of Sigma and Chi Phases in a Cast Super Duplex Stainless Steel

• Tipo: Artigo em Revista Científica Internacional
• Data: 2019-08-19

Autores

Ricardo O. Sousa (Autor) FEUP; Laura Ribeiro (Autor) FEUP; P. J. Ferreira (Autor) Outra; P. Lacerda (Autor) Outra

Revista

Título: Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

Vol. 50A Nº 10

Páginas: 4758-4778

ISSN: 1073-5623

Editora: Springer Nature

Indexação

ISI Web of Knowledge - 0 Citações

Scopus - 6 Citações

Outras Informações

ID Authenticus: P-00Q-Z3Y

DOI: 10.1007/s11661-019-05396-6

Abstract (EN): Super duplex stainless steels are prone to the formation of undesirable secondary phases, particularly when exposed to slow cooling rates. In the current study, the mechanisms of formation of secondary phases have been characterized using a combination of optical microscopy, scanning electron microscopy, and transmission electron microscopy, on samples aged at temperatures ranging between 700 degrees C and 1000 degrees C. Among the possible secondary phases, chi-phase and sigma-phase were detected and identified as the main phases responsible for the destabilization of the duplex microstructure. The kinetics of both phases were assessed. In particular, the chi-phase forms prior to sigma-phase, until it starts to convert into sigma-phase. Finally, the TTT curves for the stable sigma-phase were calculated. We found that the precipitation of the sigma-phase starts as early as 30 seconds at 950 degrees C.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 21