Microstructure Modeling of Dynamically Recrystallized Grain Size of Sintered Al–4 wt % B4C Composite During Hot Upsetting

Grain size control of any engineering metal is very important in the hot upsetting process. Generally, the grain size directly controls the mechanical properties and performance of the material. Al–B4C composite finds extensive applications in nuclear industries, defense, and electronic industries. Therefore, the aim of this work is to study the dynamic recrystallization (DRX) behavior of Al–4 wt % B4C composite during the hot upsetting test. Experimental work was performed on sintered Al–4 wt % B4C preforms at various initial relative density (IRD) values of 80%, 85%, and 90%, and over the temperature range of 300–500 °C and strain rates range of 0.1–0.3 s−1. The DRXed grain size of Al–4 wt % B4C preforms for IRDes, and temperatures and strain rates were evaluated by using an optical microscope. The activation energy (Q) and Zener–Hollomon parameter of sintered Al–4 wt % B4C preforms were calculated for various deformation conditions and IRDes. The mathematical models of DRX were developed as a function of Zener–Hollomon parameter for various IRDes to predict the DRXed grain size. It was found that the DRXed grain size decreases with increasing Zener–Hollomon parameter. Verification tests were done between the measured and predicted DRXed grain size for various IRDes, and absolute and mean absolute error was found to be 9.92% and 8.58%, respectively.