Titanium alloy raw materials for aviation forgings ━ bar wheel, casing, integral blade, fan blade and other large forgings generally adopt large size bars for small compressor blade, turbine blade forgings adopt small size bars. As the advanced engine tends to adopt the structure form of integral blade disc and integral blade ring, the size of the forgings and bars should be increased accordingly. It is very important to control the organization uniformity of large bars to ensure the quality star of the forgings. It is necessary to choose the appropriate forging equipment to optimize the design of the forging process. For the ingot of TB12 and TiAl alloy, due to the high deformation resistance of the as-cast metal, low process plasticity, sensitive to deformation temperature, and easy to crack, it is recommended to adopt the high temperature extrusion billet process to prepare large size bar, which can not only improve the uniformity of deformation and ensure sufficient safety, but also improve the production efficiency and batch stability of the bar.
The microstructure and crystallographic texture of titanium alloy are the main factors affecting the mechanical properties due to the anisotropy of α phase. Controlling the microstructure morphology and the uniformity of microstructure and texture of forgings can not only improve the average performance level, but also improve the dart-fatigue interaction performance of parts, i.e. load retention fatigue performance, and reduce the dispersion of performance data of different batches of parts. For these new high temperature titanium alloys, especially TA alloy, the introduction of ordered structure makes the texture problem more complex and important, and the influence of high and low cycle fatigue properties and load maintenance fatigue properties is also more complex. The structure and texture should be strictly controlled during the preparation of bars and forgings.
Due to the continuous improvement of advanced engine performance, integral blade disk and integral blade ring have become the development trend. The structure of the integral disk blade is complex, the opening of the channel is poor, the blade is thin, the bending and torsion is large, the rigidity is poor, and the deformation is easy. In the design, the geometric accuracy level and the comprehensive quality level are required to be higher and higher. The guarantee of machining and surface integrity becomes more and more difficult. For the compressor integral blade disk and annular blade profile with small blade size, high-speed numerical control milling method is generally adopted to control the machining deformation of parts. Vibration light finishing stress removal technology is adopted to improve the residual stress distribution on the surface of parts. Then, partial blade profile is polished and abrasive flow polishing is carried out The pm level improves the surface quality and surface integrity of parts. The profile of TiAl alloy blade should be processed by electrochemical method.