基于DMR的钛合金片层组织热变形应变局部化仿真建模研究

The crystal plasticity finite element model (CPFEM) based on titanium alloy colony was established using DMR technique, and the model was used to study the strain localization of titanium alloy colony in hot working. The model mainly included high fidelity extraction of lamellar colony, crystal orientation reconstruction of high temperature β parent phase and initial anisotropic resistance of slip systems. The evolution of strain localization in hot stretch and its effect on lamellar colony were studied. The evolution law of local Schmid factor of α and β phase was analyzed and the formation mechanism of strain location was also investigated. It is found that the strain localization band is generated in β parent phase along the direction of lamellar colony. With the increase of engineering strain, multiple localization bands are connected to each other and finally across the whole β phase. The physical mechanism of strain localization evolution is that the strain localization of β parent phase at high temperature leads to the start of the hard slip system of the adjacent α phase, which leads to the stress concentration in α phase. The stress concentration of α phase also leads to further enhancement of corresponding strain localization of β phase.