Fatigue Life Analysis Of Aircraft Compressor Blade Based On TC11 Electrical Pulse Modification Study

The technology of electric pulse processing is an efficient and green modification technology of metal materials.The study of this technology is of great significance to material science and sustainable development in our country.In this paper,TC11 titanium alloy for aviation is electropulsed to study the effect of pulse current on its mechanical properties,and the mechanism of electric pulse is explored from many aspects.Then,fatigue life simulation of compressor blades made of TC11 titanium alloy material is performed to verify the effect of pulse current modification at the component level.The change of the surface temperature of the sample during the electric pulse processing was firstly observed by using an infrared thermal imager.Then,tensile properties and fatigue properties of standard TC11 test bar before and after electric pulse processing were tested by tensile tester and high-frequency fatigue tester.And the fatigue life of TC11 titanium alloy under stress 625 MPa was proved to be subject to normal distribution by P-N diagram method.Changes in microstructure,fatigue and tensile fracture,resistivity and microhardness of α phase of TC11 titanium alloy after electrical pulse processing were observed by metallographic microscope,3D optical microscopy and SEM,resistivity tester andmicrohardness tester.Combined with the measured parameters in the tensile test to made static analysis of the aircraft compressor blade made of TC11 titanium alloy by Ansys Workbench,and obtained the dangerous point of the blade.Finally,using the static analysis results and the S-N curve obtained from fatigue test to calculate the fatigue life of blades before and after electric pulse processing.And this process used the nominal stress method and Miner’s cumulative damage rule.The results show that the plasticity of TC11 titanium alloy increases by 11.3%,and the S-N curve moves up,and the fatigue limit increases by 19.3 MPa,but the elastic modulus and tensile strength remain unchanged after electric pulse processing.The pulse current processing makes the temperature of TC11 increase rapidly,which leads to the local recrystallization to produce fine grain,thus improving the tensile properties of the material.After electric pulse processing,the dimples of tensile fracture of TC11 titanium alloy is less and deeper.The crack propagation patterns are clear and regular on the fatigue fracture.The fatigue crack source moves inward,the microhardness of the α phase increases by 14.9 HV,and the resistivity decreases by 0.433 mΩ·mm.The internal temperature field of the material caused by electric pulse treatment is applied to the microscopic defect,which causes the compressive stress between the defect and the matrix.This compressive stress can promote the microcracks healing,and also make the meshing between the impurity and the substrate is higher,so the germination probability of internal microcracks of TC11 Titanium Alloy is reduced under the force.And stress relaxation occurs in the internal stress concentration of the material,which makes its microstructures to a more uniform and stable state,so that the mechanical properties of TC11 titanium alloy are improved.The fatigue life simulation results show that compared with compressor blades made of untreated materials,the fatigue life of the blades made of TC11 titanium alloy increases by 280500.