Theses and Dissertations

Issuing Body

Mississippi State University


Horstemeyer, F. Mark

Committee Member

Solanki, N. Kiran

Committee Member

Bammann, J. Douglass

Committee Member

Castanier, P. Matthew

Date of Degree


Document Type

Graduate Thesis - Open Access


Mechanical Engineering

Degree Name

Master of Science


James Worth Bagley College of Engineering


Department of Mechanical Engineering


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.