A strategy to quantify the second phase strengthening of α precipitates in titanium alloys is proposed to predict the mechanical performance through crystal plasticity finite element (CPFE) models. Considering the different dominant features of equiaxed and lamellar microstructures, statistical and microstructural factors are introduced to describe the slip resistance variations in the β matrix. The significant contribution of the interfaces is incorporated by introducing the interface-affected zone (IAZ) into crystal plasticity constitutive laws of equiaxed microstructures. In particular, the slip resistance variation is derived accounting for the interfacial energy distribution inside the IAZ. Meanwhile, the arrangement of the α lamellae is more compact and complex than that of spherical α grains in equiaxed microstructures; thus, instead of the IAZ, the interface length density is applied to describe the strengthening effects of the interfaces in lamellar microstructures. The elastic interaction energy induced by the semi-coherent interfaces of lamellae is obtained according to the micro-elastic theory. Using the advantages of the aforementioned improved models, CPFE simulations of the tensile behavior of equiaxed and lamellar microstructures at room temperature are performed, with the results matching well with the experimental data. Moreover, differences regarding the lattice structures and grain orientations lead to non-uniform strain partitioning in equiaxed and lamellar microstructures. Equiaxed α grains that favor prismatic slip tend to bear more plastic deformation than those favoring basal slip. The growth direction of α lamellae affects the deformation ability as well. Consequently, the proposed approach can precisely predict the mechanical properties of dual-phase titanium alloys through statistical values of microstructural features, and can be utilized in the investigations of other metals with similar structural characteristics.

提出了一种量化钛合金中α析出物第二相强化的策略，以通过晶体塑性有限元（CPFE）模型预测力学性能。考虑到等轴和层状微观结构的不同优势特征，引入统计和微观结构因素来描述β基体的抗滑性变化。通过将界面影响区 (IAZ) 引入等轴微结构的晶体塑性本构规律，可以将界面的重要贡献纳入其中。特别是，考虑到 IAZ 内的界面能量分布，推导了防滑性变化。同时，等轴组织中α片层的排列比球状α晶粒更致密、更复杂；因此，用界面长度密度代替 IAZ 来描述层状微结构中界面的强化效果。根据微弹性理论，得到片层半共格界面引起的弹性相互作用能。利用上述改进模型的优点，对等轴和层状组织在室温下的拉伸行为进行了CPFE模拟，结果与实验数据吻合良好。此外，晶格结构和晶粒取向的差异导致等轴和层状微结构中的应变分配不均匀。有利于棱柱形滑移的等轴 α 晶粒往往比有利于基面滑移的等轴 α 晶粒承受更多的塑性变形。α薄片的生长方向也会影响变形能力。因此，所提出的方法可以通过微观结构特征的统计值精确预测双相钛合金的力学性能，并可用于研究具有相似结构特征的其他金属。