Research On Creep-Fatigue-Damage And Micro-michenism Of GH4133B Supperalloy Used In Turbine Disk Of Aero-engine

With the rapid development of science and technology,aviation industry of China has entered a new era.The practical application of modern aviation engine put forward higher requirements for supperalloy,so it is necessary to consider all aspects of the comprehensive performance of alloy.Compared with the normal temperature,under the condition of high temperature material mechanism is quite different from the performance in a certain force,creep damage,creep fatigue damage and thermal mechanical chemical coupling damage of material are produced.In general,the study of crack propagation in high temperature environment is based on the principle of linear superposition.However,due to the influence of creep and fatigue,the interaction influence can not be ignored.This paper will discuss the fatigue damage mechanism of the material.it include three aspects as follow: the theoretical analysis of creep fatigue damage,experimental research and micro mechanism.GH4133B Supperalloy Used in Turbine Disk of Aero-engine as the research object,in oxygen environment this paper will to carry out the fatigue damage and creep fatigue damage test,analysis the difference between micro damage mechanisms of the room temperature and high temperature;after the completion of the creep fatigue tests,using SEM(scanning electron microscopy)and EDS spectrometer scanning analysis of the fracture surface.The conclusions are as follows:1.Creep deformation of alloy GH4133 B at high temperature changes with the fatigue cycle changes.Material creep is mainly divided into three stages,including rapid growth phase,stable phase,accelerated growth phase.On stable stage,there is obvious step phenomenon for further observation,it may be dueing to the sliping inside the material.2.The creep fatigue interaction of the material at high temperature can accelerate the deterioration of the material,and dramatically reduce the service life of the material.At the same time,the creep fatigue interaction needs to meet certain external conditions.Materials in the stress ratio is around 0.1,prone to creep fatigue interaction,namely creep parameters and parameters of fatigue ratio is 0.8,prone to creep fatigue interaction;second,the material to be violent creep fatigue interaction must have larger creep strain value.The test results show that the stress value is about 330 MPa.3.Comprehensive observation of fracture morphology can be found that the creep fracture hole is the biggest when stress ratio is around 0.1.This may be because the material of the violent creep fatigue interaction is formed when the stress ratio is about 0.1.The creep stress and cyclic stress influence with each other,which leads to the increase of the creep cavity and the decrease of the life of the material.4.Compared with the normal temperature condition,the region of fatigue source region becomes narrow in high temperature.The number of secondary cracks increase in high temperature,it may be due to creep cavity confluent.The shape of dimple is similar with creep cavity,however the high temperature creep cavity size is bigger than dimple size.With stress increases,the dimple size decreases.With loading stress increased,creep cavity size also increased.At the same time,creep fatigue interaction effect will make creep cavity size significantly increased.5.The oxygen content is relate to the crack propagation direction.The closer to the crack nucleation,the higher with oxygen content.The oxygen content decreased gradually along the direction of crack propagation.At the same time,in different positions of the same crack length,there is not obvious vary with oxygen content.It indicated that the oxygen element content associated with crack length.