Physical Modeling of Flow Stress during the Hot Deformation of Nb Steels

Abstract:

In order to provide an accurate prediction of the flow stress during the thermal deformation process, a physical model is established. In the model, it is assumed that the flow stress is mainly composed of short-range stress and long-range stress. The short-range stress is a friction stress needed to be overcome when dislocations pass short-range obstacles and through the lattice, and the long-range stress is athermal stress caused by the interaction of dislocation substructure. The model is established mainly based on the evolution of dislocation density which is described as a competitive process of work hardening and recovery. Meanwhile, the interaction between vacancies and dislocations is also taken into account. The effect of solutes and precipitation on stress is quantified. In addition, some experiments have been performed using two steels containing different amounts of Nb under various deformation conditions. The experimental results indicate the prediction accuracy of the model is satisfactory.

• Periodical: Materials Science Forum (Volume 944)
• Pages: 247-253
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.944.247
• Online since: January 2019
• Authors: Jian Wei Zhao, Quan Yang, Xiao Chen Wang*
• Keywords: Dislocation, Flow Stress, Recovery, Vacancy, Work Hardening

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