| Turbine disk is a key part of the gas turbine–engine, the material used by turbine disk is pivotal for the techno- performance,reliability and security. Following the development of high performance aero-engine, the material which is used in turbine disk is more and more stringent, namely, good integrative capability and long-term stability are demanded. In this dissertation the systemic study of powder metallurgy is performed. Based on the present study, the mechanics performances of Powder Metallurgy(PM) Ni-base Superalloy are systemic studied by experiment. And then, integrating with engineering, the fatigue life and burst speed of the real turbine disk are studied, and some useful exploring works of the applying of the PM is carried out. The main works and contributions of this dissertation are listed as follow.1,The experiment study of high temperature alloy material FGH95 is carried out,and the basic mechanical performances are griped. From the experiment study, it can be seen that nickel-base powder metallurgy (PM) FGH95 superalloy is strain hardening material. The experimental results of tensile testing show that the effect of strain rate on the Young's modulus, tensile yield strength, and plastic modulus can be neglected at temperature from 420℃to 650℃. On mode R=-1, the influence of temperature on low cycle fatigue life can be ignored. But on mode R=0, the influence of temperature on low cycle fatigue life is serious. Compared with the tensile test results, the compressive strength limit and the compression fatigue life of PM is very high, and exceed a half of the tensile strength limit of PM. From the experiment results of creep, it show that the influence of temperature and stress level on FGH95 is evident. Along with the increasing of the temperature and stress level, the resistance of creep deformation of PM decreases quickly. Form the fatigue crack expand test it concludes that the fatigue crack expand speed is closed between the test temperature 420℃and 650℃.2,Based on Gurson's model, analysis of finite deform plastically damage for tension specimen has been analyzed in PM alloys including inclusions. Special attentions have been paid on the influence of the location and shape as well as size of the inclusions on the void enlargement, nucleation and stress redistributing. It has been found that the influence is much high. Therefore the life of the PM alloys is also influenced by the above inclusion information. The simulation results shows that the distance between inclusion and surface have much influence on the damage of matrix. The inclusion nearest surface is the main factor that causes the fracture of the powder metallurgy materials.3,The fatigue study is carried out on the powder metallurgy materials with inclusion using Gurson model. The research shows that the shape of inclusion has strong influence on the fatigue strength of matrix. The max VVFG of matrix decreases with the increasing of the cycle loading. The result shows that the accumulation of VVFN is the main reason which causes damage of material.4,Numerical calculation with K-R damage law has been performed to study the creep damage of power metallurgy material under multiaxial stress states. The calculation results show that the notch shape has much influence on the maximum creep damage distribution. Notch radius has a great influence on creep life. For C-type and U-type notched specimen, the creep life decreases with notch radius increasing. For the V-type notched specimens, the rupture life decreases with increasing the notch angle. The low-cycle fatigue (LCF) behavior of smooth round specimen and a plate containing holes specimens made of powder metallurgy superalloys (FGH95) is studied by experiment and finite element method at different temperatures. A low-cycle fatigue life model has been proposed for the powder metallurgy superalloys under multiaxial stress states. The LCF life is a power function of true stress range corresponding to the maximum and minimum loadings. Further, a simulating specimen of turbine disk has been studied to validate the LCF life model. Good agreement has been obtained between finite element analysis and experimental results.5,In order to assure the security of PM turbine disk, the stress distributing of turbine disk is calculated by FEM. The danger point of turbine disk is found. Based on the formulation of stress range and fatigue life, the cycle number of turbine disk is estimated, which is accordant with the test result. The burst speed of turbine disk is calculated by the use of three different methods, those are the equality stress method, the small deformation analytic method and the large deformation analytic method, and the results are compared with the test. The calculation results show that the values of numeration are closed to the experiment value, and the value of large deformation analytic method is more secure.6,The distributing of stress and strain of turbine disk is computed using of two different FEM models, which are calculated the effection of ventilating hole and the cut of the disk. The results of calculation show that the stress concentration is serious because of the lack of circle angle in the root of the cut. This is the main factor for the sprout of crack, and finally induces the breakage of the disk. This conclusion is consistent with the experiment result. At the same time, the fatigue life of the disk is analyzed by numerical simulation and the photo of SEM. From the interval of fatigue strip, the formulation of the extend velocity of fatigue crack can be established, which can be used to estimate the sprout life and the extend life of the fatigue.
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