揭示Ti合金复杂微结构特征与其力学行为之间的内在关系对于充分挖掘其应用潜力具有重要意义，但现有试验手段难以对特定载荷作用下的微结构演化过程进行实时跟踪和量化表征，且基于二维微观组织照片的有限元建模及模拟与真实的微结构特征及服役环境并不一致。本项目将克服上述局限，以α+β两相Ti合金TC4为研究对象，通过所提出的MicroCT三维重构与建模、单相本构模型构建及参数获取、介-宏观尺度关联方法等系列技术，实现材料在准静态及高应变率条件下微观组织的演化过程模拟，近真实的再现应力场、应变场等关键参量在不同相及各个晶粒内部的三维空间分布特征；揭示出不同相之间的相互作用机制，以及相比例、相尺寸、相取向、相分布等结构因素对其力学响应行为的影响规律，从而更为深入地揭示Ti合金微观组织的变形及失效机理，为该类材料的优化设计提供理论指导。相关工作对于其他多相合金类材料的研发也具有重要的技术支撑作用。

Establishing the underlying relationship between titanium alloy’s complex microstructures and its mechanical behaviors is significant for promoting titanium’s practical applications in industry. Unfortunately, microstructure evolution and response to a specified mechanical load are hard to be tracked or quantificationally characterized using the current experimental techniques. In addition, finite element modeling based on two dimensional microstructure pictures is inconsistent with the actual microstructure characteristics and the true service conditions. The methods proposed in this project will break through such limitations by focusing on the α + β dual titanium alloy TC4, including three dimensional (3D) microstructure reconstruction based on MicroCT, constitutive equation establishment and parameter fitting for the individual phase, and meson-macro multiscale modeling. In this way, the realistic microstructure evolutions under quasi-static or high strain-rate loadings are expected to be simulated, and the stress/strain fields in different phases or grains can be captured in 3D space, so as to reveal the interaction mechanisms between individual phases. Furthermore, effects of phase ratios, sizes, orientations, and distributions on titanium alloy’s mechanical behaviors will be discussed, and the underlying deformation or failure mechanisms are expected to be unraveled theoretically, which would be helpful to optimize microstructures of titanium alloys. Methodologies proposed in this project can also support developments of other multi-phase alloys.