A Microstructure-based dynamic recrystallization model for dry machining of AISI 4140 with in-situ kinematic and thermal calibration and validation

A calibration methodology for physics-based dynamic recrystallization (DRX) modelling in machining is pre-sented, based on full-field, in-situ thermal and kinematic measurements based on high-speed digital image correlation (DIC). Streamline-resolved shear strain histories obtained from DIC are used to constrain DRX activation in terms of the critical and saturation dislocation densities of a microstructure-based model. Local tool chip interface temperatures are independently measured using three integrated thin-film thermistors.
The methodology is demonstrated for dry orthogonal cutting of AISI 4140, where predicted recrystallized layer depths Zgs show good agreement with focused-ion-beam (FIB) cross-section measurements. The results establish DIC-based kinematic calibration as a robust and physically grounded route for microstructure modelling.