Microstructure Prediction for Cryogenic Cutting Using a Physics-based Material Model

Cryogenic cutting has been demonstrated as an effective machining process for magnesium (Mg) alloy to improve its machined surface integrity. Previous numerical studies on cryogenic cutting are mostly based on phenomenological material constitutive models, and have not considered the material twinning response during the process. In this paper, a physics-based constitutive material plasticity is developed based on both slip and twinning mechanisms and applied to model the microstructural evolution during cryogenic cutting of AZ31B-O Mg alloy. The FE model results are further discussed in terms of grain size, microhardness, residual stress, and slip/ twinning transition during the cryogenic cutting process.