Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Horstemeyer, F. Mark

Committee Member

Solanki, N. Kiran

Committee Member

Bammann, J. Douglass

Committee Member

Castanier, P. Matthew

Date of Degree

5-1-2011

Document Type

Graduate Thesis - Open Access

Degree Name

Master of Science

Department

Department of Mechanical Engineering

Abstract

The present study develops a phenomenological adaptation to an internal state variable (ISV) model that incorporates the influence of dynamic recrystallization (DRX) in a material’s evolving microstructure and flow stress response. During metal forming and joining processes that promote internal heat distributions and large strains, microstructural processes often occur that result in a transformation of the evolving microstructure away from the base distribution. In an effort to lower the stored energy accumulated in the material’s lattice and grain structure, the deformed material may undergo a type of dynamic recovery process, such as DRX. In this study, the ISV model’s flow stress output is modified to include a phenomenological DRX softening and hardening term internal to the isotropic hardening rate ISV. The flow stress thus directly includes the influence of microstructure evolution. The evolving grain size is modeled such that an inverse relation exists between strain hardening and average grain size.

URI

https://hdl.handle.net/11668/15213

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