Numerical modeling on strengthening mechanisms of the harmonic structured design on CP-Ti and Ti-6Al-4V

The present work investigates and compares the deformation mechanism of harmonic structured (HS) CP-Ti and Ti-6Al-4V alloy to that of homogeneous coarse-grained (CG) counterparts. A set of simple shear tests on homogeneous CG and HS specimens for CP-Ti and Ti-6Al-4V was conducted under monotonic and cyclic simple shear loading conditions. Efforts have been made to develop a numerical model which is aimed to investigate the microstructure-related mechanical behavior of the materials. Numerical and experimental results were confronted to confirm the validity of the proposed model. To better understand the strengthening mechanisms of the HS design, comparisons between HS CP-Ti and HS Ti-6Al-4V were conducted and discussed in terms of macroscopic stress-strain response and distribution of stress/strain fields. Furthermore, forecasting mechanical properties of HS CP-Ti and HS Ti-6Al-4V including various volume fractions of fine-grained (FG) regions were simulated by using the developed model. It was demonstrated that strengthening mechanisms of harmonic designed CP-Ti and Ti-6Al-4V structures are different. This result explains why the HS design induces superior strengthening effect on CP-Ti than on Ti-6Al-4V.