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Indexed by:期刊论文

Date of Publication:2018-09-01

Journal:JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE

Included Journals:SCIE

Volume:27

Issue:9

Page Number:4955-4967

ISSN No.:1059-9495

Key Words:cellular automaton; dislocation density model; dynamic recrystallization; nickel-base superalloy; nucleation model

Abstract:A modified cellular automaton (CA) model in the time and space scale is developed to simulate the dynamic recrystallization (DRX) mechanism of Nimonic 80A nickel-base superalloy during hot deformation. Some necessary thermo-mechanical parameters used as input data in CA approach such as work hardening and softening coefficient are fitted according to the previous hot compression experiments. Based on the experimental results, nucleation kinetics is modified as a function of Zener-Holloman parameter. A dislocation density model at transient recrystallization boundary is proposed, in which the dislocation density is a function of temperature, strain rate and annealed dislocation density. The simulated results are in good agreement with experimental results, proving that the modified CA model is capable of predicting both flow behavior and microstructural evolution of Nimonic 80A during hot deformation. According to the experimental and simulated results, the DRX behavior is discussed in detail. It demonstrates that the flow stress and microstructural evolution of DRX have a relationship with the deformation temperature and strain rate.