Numerical Simulation For The Isothermal Forging Processes Of Complex Structural Component Of Ti-1023 Alloy

The comprehensive requirement for both the integrality of structural components and the benefit from them are more rigorous than that ever before as the rapid development in aerospace industry. Therefore, the deliberate design and utilization of materials for the structural components, as well as the cost for producing them, become essential. Titanium alloy, an excellent combination of strength, density, ductility, and toughness, has become a key material and are increasingly attractive in aerospace industry.Compared to other a+p alloys, Ti-1023, a metastable β -Ti alloy, exhibits higher strength/density ratio and good hardenability. Furthermore, the β -transus temperature and the processing temperature of Ti-1023 are relatively lower than the others, and thus make it more suitable for manufacturing complex structural components by isothermal forging processes.In this thesis, a novel constitutive relationship as a function of Zener-Hollomn parameter was formulated for Ti-1023 alloy based on the experimental results of isothermal constant strain-rate compression test. This relationship can represent properly the dynamic behavior of hot deformation of Ti-1023 alloy.The processing maps for Ti-1023 alloy were constructed based on the Mals and Seetharaman's criteria. These maps lay foundation on evaluation quantitively the quality of the forgings and the fitness of forging process for Ti-1023 alloy.Numerical simulation based on FEM has become a powerful tool on analyzing forging process. In this paper, 3-D numerical simulations for isothermal forging processes of a complex structural component of Ti-1023 alloy were performed by using of MSC.Superform software. The effect of initial configuration of billet on the capability of die filling, the uniformity of strain and temperature distribution within workpiece were analyzing quantitively. Based on the result, an optimal configuration of the billet was proposed.Finally, the quantitively evaluation for different forging processes by using of Quality Loss Function(QLF) was performed. The results show that the best consistency of microstructure and property within the workpiece can be obtained by using the proposed optimal billet.