Microstructural based constitutive modeling and subsurface microhardness prediction in machining of network-structured TiBw/TA15 composites

There is a gap that should be filled in a deeper understanding of the potential role played by multiple microstructures in the material mechanical properties during the machining of network-structured TiBw/TA15 composites. In view of this, a comprehensive constitutive model is established coupled with the shear lag theory and Weibull distribution for the TiBw/TA15 composites. Whereby, the multi-step finite element (FE) simulations considering the multiphase microstructures are adopted to determine the local equivalent (LE) constitutive function of network boundary region (NBR). And the initial parameter identification and model modification are completed with the SHPB data and the DIC-based analytical results of the micro-scale orthogonal machining process, respectively. The proposed constructive model with high fitting precision enables the quantification of the effective strengthening effect from TiBw and the equivalent stress from TA15 matrix. Subsequently, the established constructive model can be utilized to construct the theoretical yield strength field in the machined subsurface with the help of the conventional analytical modeling method. And the semi-analytical modeling technique is developed and validated using the theoretical yield strength as an index to predict the subsurface microhardness. Furthermore, the internal mechanism derived from the constitutive model provides some explanation for the microhardness variation analysis.