Austenite reversion in AISI 201 austenitic stainless steel evaluated via in situ synchrotron X-ray diffraction during slow continuous annealing

• Autor: Isnaldi Rodrigues de Souza Filho
• D. R Almeida Junior; Christian Gauss; Maria Jose Ramos Sandim; Paulo Atsushi Suzuki; Hugo Ricardo Zschommler Sandim
• Assuntos: MATERIAIS; In Situ Xrd Synchrotron; Austenite Reversion; Modified Williamson-Hall; Diffusion-Controlled Mechanism; Aisi 201 Steel
• É parte de: Materials science and engineering a-structural materials properties microstructure and processing v.755, p.267-277, 2019
• Notas: Disponível em: https://doi.org/10.1016/j.msea.2019.04.014. Acesso em: 04 jan. 2024
  
• Descrição: In situ synchrotron X-ray diffraction was used to track real-time austenite reversion in AISI 201 austenitic stainless steel deformed to a true strain of 0.34 under tensile testing. The deformed material was continuously annealed from 100 °C up to 800 °C at a heating rate of 0.05 °C s−1. Phase changes and microstrain partitioning were evaluated by means of the direct comparison method and modified Williamson-Hall plots, respectively. The microstructure of the deformed steel consists of γ, ε- and α′-martensite with volume fractions of 0.24, 0.07, and 0.69, respectively. ε → γ reversion occurs within the temperature range of 150–400 °C through a shear mechanism. The starting (As) and finishing (Af) temperatures for α’ → γ reversion are 486 °C and 770 °C, respectively. Three stages were distinguished for this reaction. By evaluating the crystallite size of both γ- and α′-phases, it can be inferred that α' → γ reversion is diffusion-controlled. Such results were corroborated by thermodynamic simulations to assess the driving force for γ-formation. Microstructural aspects such as γ-nucleation sites, in-grain misorientation, grain refinement, and crystallographic texture were investigated by means of electron backscatter diffraction. Fresh formed ultrafine austenite grains hold different crystallographic orientations than those of untransformed austenite.
  
• Editor: Oklahoma Elsevier
  
• Data de criação/publicação: 2019
  
• Formato: p. 267-277.
  
• Idioma: Inglês