涡轮叶片残余应力场对精铸变形及再结晶的影响与控制方法研究

There are some problems in the manufacture process of single-crystal turbine blades in China, such as low forming accuracy, instable quality, and high rejection ratio. As a result, the manufacturing of turbine blades has been one of the "bottlenecks" which restricting the development of new aero-engine. The reason of low forming accuracy and recrystallization is that because of the complex structure, the residual stresses have an uneven distribution after investment casting process, which can bring the strain or the stress concentration phenomena. A control method of investment casting deformation and recrystallization of single-crystal turbine blade based on residual stress will be proposed in this project. The forming mechanism of the residual stress and the characteristic of the critical stress and the deformation will be studied. The controlling criterions of the deformation of the profile of single-crystal turbine blade and the recrystallization will be established. The unite theory of the controlling method of the recrystallization, the deformation the structure and the residual stress will be established in the project. The method of controlling the deformation based on the geometry of wax pattern and the method of controlling the recrystallization based on the access structure of wax pattern will be built up. This project will provide reliable guarantee for the realization of the precise control of single crystal turbine blade shape and the elimination of the recrystallization.

国内单晶涡轮叶片成形精度低、质量不稳定、表层再结晶现象严重，废品率高已成为限制我国高性能发动机研制的瓶颈。其中再结晶及成形精度低的问题根源在于具有复杂结构的涡轮叶片精铸残余应力分布不均，产生了应变或局部应力集中。本申请拟针对航空发动机单晶涡轮叶片变形及再结晶问题提出基于残余应力的控制方法。针对单晶涡轮叶片铸造残余应力的产生机理与再结晶临界应力特性和变形特性进行系统深入的研究，建立单晶涡轮叶片型面变形与再结晶的控制准则，构建单晶涡轮叶片再结晶及精铸变形与结构形状和残余应力的一体化控制理论。建立基于蜡型形状优化的叶片铸件变形控制与基于蜡型工艺辅助结构的残余应力与再结晶控制方法。为实现单晶涡轮叶片铸件精确控形与消除或抑制再结晶提供可靠保障。

国内单晶涡轮叶片成形精度低、质量不稳定、表层再结晶现象严重，废品率高已成为限制我国高性能发动机研制的瓶颈。其中再结晶及成形精度低的问题根源在于具有复杂结构的涡轮叶片精铸残余应力分布不均，产生了应变或局部应力集中。本项目拟针对航空发动机单晶涡轮叶片变形及再结晶问题提出基于残余应力的控制方法。针对单晶涡轮叶片铸造残余应力的产生机理与再结晶临界应力特性和变形特性进行系统深入的研究，建立单晶涡轮叶片型面变形与再结晶的控制准则，构建单晶涡轮叶片再结晶及精铸变形与结构形状和残余应力的一体化控制理论。建立基于蜡型形状优化的叶片铸件变形控制与基于蜡型工艺辅助结构的残余应力与再结晶控制方法。为实现单晶涡轮叶片铸件精确控形与消除或抑制再结晶提供可靠保障。