为弥补经典理论不能准确预测钛合金片层α相各向异性长大的缺陷，并建立片层组织特征参数的分布与屈服强度的关系，本项目结合实验表征、理论建模和计算，开展基于联合概率分布的片层α相形核与各向异性长大动力学研究，并以近β型Ti-1023和Ti-5553合金进行例证。项目从α片层尖端和宽面形核率的联合分布出发，建立新模型；在物质守恒和可变长宽比的球冠几何条件下，计算不同界面尺寸和成分的演化，揭示多组元耦合作用对β/α界面移动的影响机制，探明Gibbs-Thomson效应引起的近场扩散对α尖端和宽面形核长大的影响，为β↔片层α相变的定量调控提供理论依据；基于组织特征参数的分布演化，系统地评估屈服强度与片层组织特征平均值、极值、协方差等的关联强度，更全面地建立组织-屈服强度关系；开发具有工业应用价值的组织与性能调控软件，拓展经典方法在钛合金热处理工艺制定和力学性能预测中的应用，为我国制造业的创新做出贡献。

To expand the availability of classical methods in predicting the behaviors of anisotropic growth and correlate the distribution of microstructure features to the yield strength of alloys, the project investigates the kinetics of nucleation and anisotropic growth of lamellar α phase in multicomponent near β titanium alloys based on the concept of joint probability distribution. It is a comprehensive research by combining microstructure characterizations, theoretical analyses and numerical simulations. We first modify the classical models of nucleation, growth and coarsening by introducing a joint probability distribution of nucleation density for tips and broad faces in lamellar α phase and then calculate the evolution of sizes and chemical compositions under the constraints of mass conservation and geometry of spherical crown. The model is validated against the experimental findings in Ti-1023 and Ti-5553 alloys. With the modeling, the changes of phase stability and the auxiliary diffusion flux due to the Gibbs-Thomson effect are to be evaluated. The role of multicomponent chemical coupling on interface migration is to be figured out. The captured mechanisms can help to precisely control the β↔ lamellar α phase transformation in industry. Subsequently, the distribution information of microstructure features will be passed to the internal-variable method to predict the yield strength of alloys. Not only mean values of microstructure features but also extrema and covariance of them are considered. We evaluate the weights of these statistical parameters in the determination of yield strength. The model and the simulation tool will be packaged in a software. The software together with the methodology opens a new window for application of physical metallurgical modeling in processing. It helps to optimize the processing parameters of heat treatment and is capable of predicting mechanical properties, thus does contributions to Chinese innovations in manufacture.