晶体塑性模型将金属材料的塑性变形与微观组织演化相统一，为更好地理解钛合金高温复杂变形机制和预测不同应变路径下的成形极限提供了一种强有力的工具。本工作基于TA32钛合金板材的微观组织及晶体取向建立了一种考虑损伤演化的晶体塑性有限元(CPFE)模型，并通过耦合CPFE模型与M-K凹槽理论预测了TA32板材在750 ℃下的成形极限图(FLD)。结果表明，所提出的CPFE模型准确地预测了TA32板材在750 ℃不同应变速率下的宏观力学响应、微观非均匀变形和损伤演化行为。在不同应变路径下，原始板材中基面双峰织构的基面滑移系和柱面滑移系均难以被激活，导致其比横向织构更容易诱导损伤。采用CPFE-M-K耦合模型预测的FLD与实验结果吻合良好，并准确捕捉到了等双轴拉伸区域附近极限主应变降低的现象，分析表明其与材料力学性能的各向异性密切相关。此外，CPFE-M-K耦合模型中凹槽初始倾角的改变会显著影响TA32板材成形极限的预测精度，应变增量比为-0.5~0.5和0.6~1.0范围内的临界初始倾角分别为0°和90°。

Forming limit diagram (FLD) is a crucial tool for assessing the formability of sheet metals under various forming conditions. However, conducting FLD experiments can be challenging and time-consuming requiring numerical determination of FLDs. Marciniak-Kuczyński (M-K) theory is one of the most well-known instability criteria for calculating forming limits, and the rapid development of crystal plasticity models provides a feasible framework for better understanding the relation between flow localization and material microstructure. Therefore, integrating the M-K theory with advanced crystal plasticity models offers a potential approach to precisely predict forming limits and explore the complex interaction between material behavior and microstructural characteristics. In this study, a crystal plasticity finite element (CPFE) model considering damage evolution was developed based on the microstructure and crystal orientation of a TA32 titanium alloy sheet. The material parameters for the proposed model were calibrated through uniaxial tensile tests and microstructure characterization. The internal correlation between damage evolution and the dislocation slip mechanism under different strain paths was analyzed at the grain scale. Additionally, the FLD of the TA32 sheet at 750 ^oC was predicted by coupling the CPFE model with the M-K theory. The results show that the proposed CPFE model accurately predicts the macroscopic mechanical response, microscopic inhomogeneous deformation, and damage evolution behavior of the TA32 sheet under different strain rates at 750 ^oC. The difference in the deformation behavior and damage propagation was mainly attributed to the anisotropic activation of various slip systems. The basal and prismatic slip systems of the basal bimodal texture in the original sheet were difficult to be activated under different strain paths, making it easier to induce damage than the transverse texture. The FLD predicted by the CPFE-M-K coupling model agrees well with the Nakazima test results, accurately capturing the decrease in the limit of major strain near the equibiaxial tensile region. This decrease is closely related to the anisotropy of the mechanical properties of the material. Furthermore, the change in the initial inclination angle of the groove in the CPFE-M-K coupling model considerably affects the prediction accuracy of the forming limits of the TA32 sheet. The critical initial inclination angles within the strain increment ratio ranges of -0.5-0.5 and 0.6-1.0 are 0° and 90°, respectively.