Modelling of the impact of the thermo-mechanical load collective on the rim zone microstructure when cutting TiAl6V4

喷气发动机的旋转部件是高度安全的关键部件。在最坏的情况下，这些部件的技术缺陷可能会导致人命损失。这些组件的功能和操作行为受到组件边缘区域属性的强烈影响，而边缘区域又由最终制造过程定义。因此，机械加工过程作为生产链中的最终制造过程，对部件性能有相当大的影响。表征表面边缘区的一个重要参数是晶粒尺寸。因此，由制造过程引起的热机械载荷会影响晶粒尺寸。潜在的原因和机制是未知的，这就是为什么现有的模型来描述晶粒尺寸的变化只有不足的预测精度。在本研究项目的范围内，将开发基于模型的钛合金Ti-6Al-4V加工诱导晶粒尺寸变化的描述。为此，我们将采用热力学方法。模型的描述将通过互补的调查方法得到。一方面进行了经验加工研究及其金相评价，另一方面进行了切屑形成模拟。在经验试验的基础上测量的加工过程对材料晶粒尺寸的影响与通过切屑形成模拟计算的局部材料载荷有关。此外，将使用分析模型，它允许考虑材料的特定属性。通过建立晶粒尺寸变化模型，并将该模型集成到有限元切屑形成仿真中，可以在仿真支持的工艺设计意义上实现对切削过程对晶粒尺寸影响的连续描述。

The rotating components of a jet engine are highly safety-critical parts. In the worst case, a technical defect in those components can cause loss of human life. The functionality and operational behavior of these components is strongly influenced by the properties of the component’s rim zone, which in turn is defined by the final manufacturing process. Therefore, the machining process, as the final manufacturing process in the production chain, has a considerable influence on the component properties. An important parameter for the characterization of the surface rim zone is the grain size. Thereby, the thermo-mechanical loads that are induced by the manufacturing process affect the grain size. The underlying causes and mechanisms are unknown, which is why existing models to describe the alteration of the grain size have only insufficient predictive accuracy. Within the scope of this research project a model-based description of machining induced grain size alteration for the titanium alloy Ti-6Al-4V will be developed. For this purpose, a thermodynamic approach will be used. The description of the model will be derived via complementary investigation methods. On the one hand, empirical machining investigations and their metallographic evaluations and on the other hand, chip formation simulations are utilized. The influence of the machining process on the material’s grain size, measured on the basis of empirical tests, are related to the local material loads calculated from chip formation simulations. In addition, analytical models will be used, which allow the consideration of material-specific properties. With the model of the grain size alteration and the integration of the model into a FEM-chip formation simulation, the need for a continuous description of the effect of the cutting process on the grain size in the sense of a simulation-supported process design will be fulfilled.