| The notch effects of TC4 plasma arc welding joint under the influence of different generation mode and size is studied.So as to provide theoretical and practical basis for the reliability of plasma arc welding repairing blades.The results show that the notch sensitivity of TC4 is about 1.2 when the stress concentration factor is 3,and the notch processing method and notch size have no effect on the notch sensitivity of TC4.Although different processing methods will change the microstructure of the notch,there will be deformation residual stress and micro cracks and adiabatic shear bands in the indentation and impact notch,but under static tensile load,the tensile performance is mainly related to the size of the tensile section and the stress concentration at the notch,and the small change of notch processing method has little effect.Under the same notch size,the low cycle bending vibration fatigue life of indented and impact notched specimens is significantly higher than that of machined notched specimens,while the life of indented specimens is higher than that of impact notched specimens.The notch machining method has a significant impact on the low cycle bending fatigue performance of TC4 and its welded joints.The low cycle bending fatigue performance of the notch machined by the press in method,impact method and machining method is totally inconsistent,and the notch machined by impact method is close to the real FOD.When the stress concentration factor of the notch is fixed,the opening angle of the notch has no effect on the low cycle bending fatigue performance of TC4 and its welded joints.The smaller the stress concentration factor corresponding to the notch size is,the larger the notch low cycle fatigue life is.In the low cycle bending fatigue test,the notch fatigue life of TC4 welded joint is basically the same as that of the base metal at the low stress level,while at the high stress level,the notch fatigue life of the joint is lower than that of the base metal. |
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