基于不均匀变形协调的钛合金等温局部加载组织调控

Aiming at the coordination of unequal deformation in large-scale complex integral components isothermal local loading forming, the model based on the internal-state-variable method to predict the multi-pass macro-deformation response and microstructure evolution of TA15 Ti-alloy has been established and the simulation model and method for large-scale complex integral components isothermal local loading forming have been developed. The unequal deformation mode and laws under local loading have been revealed and affecting mechanism of local loading mode and coupled factors on the unequal deformation coordination has been proven up. The affecting mechanism of coordination of unequal deformation on precision forming of large-scale complex integral components and forming defects has been opened out. The optimal method has been proposed for local loading mode determination and design of large asymmetric preform with unequal thickness via unequal deformation coordination. As the results, 20 papers have been published or accepted, of which 5 papers were indexed by SCI, 8 by EI. Also 4 invention patents have been authorized. Based on the research above, around the microstructure regulation of Ti-alloy during isothermal local loading, taking the control of unequal deformation coordination as the main line, taking the tri-modal microsrtucture with excellent performance as target, the project is to establish microstructure quantitative characterization method of Ti-alloy under isotermal local loading, to reveal relationship and rules of local load conditions with unequal deformation and microstructure. At the same time the unequal deformation limit under the target mircostructure will be determined, further the theory and methodology will be established for microstructure regulation of Ti-alloy under isothermal local loading via optimization of the local loading conditions and unequal deformation coordination.

围绕大型复杂整体构件等温局部加载成形不均匀变形协调，建立了预测TA15钛合金多道次宏观变形响应与微观组织演化的内变量模型和大型复杂整体构件等温局部加载成形仿真方法；揭示了局部加载不均匀变形模式和规律，探明了局部加载方式等多因素对不均匀变形协调耦合作用机制；揭示了不均匀变形协调机理及其对大型复杂整体构件等温局部加载精确成形及缺陷的作用机制；提出了基于不均变形协调实现局部加载方式和大型非对称不等厚毛坯优化设计方法。撰写发表学术论文20篇，SCI/EI收录5/8篇，获授权发明专利4项。在此基础上针对钛合金等温局部加载组织调控难题，以控制不均匀变形协调为主线，以获得性能优异的三态组织为目标，研究建立钛合金等温局部加载微观组织定量表征方法，揭示局部加载条件与不均匀变形及微观组织的关联关系和规律，确定目标组织下不均匀变形极限，建立基于局部加载条件优化和不均匀变形协调的钛合金等温局部加载组织调控方法。

等温局部加载技术为钛合金复杂大件的成形提供了可能的有效途径，然而局部加载所导致的复杂不均匀变形与多道次热力参数耦合使得钛合金组织演化极其复杂、形态多样以及构件性能的多样化。基于不均匀变形协调的钛合金等温局部加载组织调控，成为钛合金等温近局部加载成形技术研究、发展及应用迫切需要解决的关键基础问题。本项目采用试验、理论分析和数值建模仿真有机结合的方法，以局部加载控制不均匀变形协调为主线，以获得性能优异的三态组织为目标，研究揭示了钛合金等温局部加载复杂不均匀变形下等轴α演化机制、锻后冷却和热处理片层α形核、生长和演化机理；探明了局部加载多因素耦合与不均匀变形对同一加载区、不同加载区和过渡区微观组织和力学性能的作用机制，建立了不均匀变形、微观组织和力学性能的关联关系；揭示了TA15钛合金等温局部加载不同区组织类型多样化以及组织不均匀形成的机制，确定了目标组织下等温局部加载不均匀变形极限；发明了锻造结合热处理获得性能优异的钛合金三态组织的方法，提出了通过局部加载条件和热力参数优化控制不均匀变形协调实现钛合金等温局部加载组织调控方法，突破了钛合金复杂大件等温局部加载高性能制造的技术瓶颈。研究成果在金属材料领域顶级期刊Acta Mater、材料成形制造领域权威期刊JMPT、JAC、MSEA等发表论文13篇（含录用），SCI收录12篇；获授权发明专利8项；获2016年国家技术发明二等奖1项（项目负责人排名第2），2014年陕西省科学技术一等奖1项（项目负责人排名第2）；应邀在国际和国内会议做特邀报告3次，为Elsevier出版社外文专著撰写1章。