Research On Creep Feed Deep Grinding Of TiAl Low-pressure Turbine Blade Tenon

TiAl alloys have high specific strength and good high-temperature performance.It could be applied to manufacture low-pressure turbine blades instead of nickel-based alloys for commercial aero-engines,which can reduce the engine weight.However,the low room-temperature ductility of this material make it a typical difficult-to-machine material.During machining,it is easy to encounter some problems such as surface cracks and surface burn.During profile grinding,the coolant is difficult to enter the grinding zone,which makes the surface burn problem more prominent.The lack of basic research on the profile grinding technology of this material is one of the important reason for the limited application of this kind of material.As a result,proposing to carry out the research on the creep feed grinding of TiAl low-pressure turbine blade tenon.The grinding features of TiAl alloy were evaluated,and the grinding wheels that can promote a better grinding performance were selected.The characteristics of temperature field distribution when creep feed grinding TiAl low pressure turbine blade tenon were discussed with the help of finite element simulation.The grinding parameters were optimized with CBN wheels in order to achieve acceptable surface integrity.The geometry accuracy was also detected.The main results and discussions are as follows:(1)Silicon carbide,microcrystalline corundum and CBN wheels were used in the grinding experiment to yield a reasonable comparison of grinding performance when creep feed deep grinding TiAl materials.The influence of the grinding parameters and the type of the grinding wheel on the grinding force was analyzed.The maximum material removal rate without grinding burnout was determined.The wheel wear behavior was discussed.It was found that,for TiAl materials,CBN wheels can result in better grinding performance than the other two types of grinding wheels.(2)The temperature features during creep feed grinding TiAl low-pressure turbine blade tenon were analyzed based on experiment and simulation.The part of the grinding heat conducting into the workpiece was determined.The effects of profile characteristics on the temperature distribution were accessed by the simulation results that was verified by experiment.The findings indicated that the grinding temperature at the top of the blade tenon is the highest one and therefore the grinding burn would easily occur.(3)The geometry accuracy and surface integrity(surface roughness,surface morphology,microhardness,residual stress,etc.)of the blade tenon were evaluated under the optimized grinding parameters,and the results indicated feasibility of creep feed grinding of TiAl alloys using CBN grinding wheels.