| Texto completo | |
| Autor(es): |
Escobar, J. D.
;
Poplawsky, J. D.
;
Faria, G. A.
;
Rodriguez, J.
;
Oliveira, J. P.
;
Salvador, C. A. F.
;
Mei, P. R.
;
Babu, S. S.
;
Ramirez, A. J.
Número total de Autores: 9
|
| Tipo de documento: | Artigo Científico |
| Fonte: | MATERIALS & DESIGN; v. 140, p. 11-pg., 2018-02-15. |
| Resumo | |
Controlling the amount of reverted austenite at room temperature allows for tailoring of mechanical properties in supermartensitic stainless steels. The austenite reversion and stabilization occurs during inter-critical tempering through partitioning of austenite-stabilizing elements. The degree of partitioning greatly depends on the reversion temperature, which dictates the local equilibrium conditions. Atom probe tomography and energy dispersive spectroscopy in transmission electron microscopy were used to study the austenite reversion mechanism in terms of the elemental distribution of austenite-stabilizing, ferrite-stabilizing and carbide forming elements. Synchrotron X-ray diffraction confirmed that the austenite equilibrium phase fraction was reached after 2.5 h of isothermal reversion at 625 degrees C, allowing for direct comparison with thermodynamic and kinetic calculations. However, such soaking time was not enough to produce compositional homogenization in the reverted austenite. The austenite reversion and stabilization mechanism was related mainly to strong partitioning of Ni. Negligible partitioning of Cr, Mo, Si and Ti were observed. Instead, these elements were strongly segregated at the reverted austenite/martensite interfaces. Carbon and Ti played a secondary role in the austenite stabilization through the precipitation of nano-sized Ti (C, N) with partial substitution of Ti by Mo. Virtually carbon-free austenite and martensite were observed away from the interfaces and precipitates. (C) 2017 Elsevier Ltd. All rights reserved. (AU) | |
| Processo FAPESP: | 16/13466-6 - Estudo correlativo por tomografia de sonda atômica e microscopia eletrônica de transmissão nas interfaces M/A, B/A e precipitados após tratamentos térmico in situ para aço inoxidável supermartensítico e aço avançado de alta resistência com efeito TRIP |
| Beneficiário: | Julian David Escobar Atehortua |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Doutorado |
| Processo FAPESP: | 14/20844-1 - Estudo in situ da cinética de transformação e a estabilidade térmica da austenita em aços avançados de alta resistência com efeito TRIP |
| Beneficiário: | Julian David Escobar Atehortua |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |