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Deformation and Annealing Behavior of an Austenitic Stainless Steel

Sadat Alavi, Parisa | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52361 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Serajzadeh, Siamak
  7. Abstract:
  8. In this research, non-isothermal annealing process at temperatures ranging between 400°C to 830 °C was investigated in warm and cold-rolled austenitic stainless steel 304L. First, the wide variety of austenitic to martensitic structure was produced by the multi-pass rolling process at room temperature -8 °C, 200 °C, and 280°C. The n exponent in Olson-Cohen equation was governed 2.83 after non-linear curve fitting to assess the fraction of deformation-induced martensite as a function of strain. Afterward, Abaqus/Explicit method was utilized to achieve the stored energy and plastic strains distribution through the thickness. Then, Cellular automata and Galerkin-finite element models were applied to determine the kinetics of static recrystallization and microstructure changes during annealing. It is worth noting that, this model was coupled with an artificial neural network to predict martensite reversion in the presence of martensite. Additionally, the effects of the initial microstructure, stored energy, and the imposed heating rate were all taken into account in the modeling. Experimentation analyses such as Vickers Hardness tests, SEM, XRD, optical microscopy and Feritscope measurements were also carried out to verify the simulation and for obtaining the constants of the model. Besides, the recrystallization-start temperature, austenite nucleation and growth activation energy in this alloy determined as 700° C, 180 kJ/mole, and 240 kJ/mole respectively
  9. Keywords:
  10. Microstructure Simulation ; Cellular Automata ; Austenitic Stainless Steel ; Static Recrystallization ; Strain-Induced-Martensite Deformation

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