A LIFE PREDICTION METHOD FOR NICKEL-BASED SUPERALLOY BLADE UNDER THERMOMECHANICAL FATIGUE LOAD

Abstract

The invention discloses a life prediction method for a nickel-based high-temperature alloy blade under thermomechanical fatigue load. It effectively solves the problem of joint characterization and life prediction of low-cycle fatigue damage, creep damage and oxidative environment damage of nickel-based superalloy blades under TMF load. Low-cycle fatigue life data, fitting the strain-life equation, combining the fatigue damage linear accumulation theory to obtain the fatigue damage model, expressing the creep damage model as a function of temperature, stress and time, and based on the continuous oxidation-cracking mechanism of the oxide layer at the crack tip To model the damage in the oxidizing environment, the continuous damage accumulation mechanism is adopted for the above three models, and the stress, strain, and temperature data of the dangerous position of the blade are used to realize the joint damage model for nickel-based superalloy components under thermomechanical fatigue loads. Accurate and reliable unified characterization and lifetime prediction of damage from fatigue, creep, and oxidation interactions.

Description

technical field [0001] The invention relates to the field of life prediction of superalloy structural parts, in particular to a life prediction method for nickel-based superalloy blades under thermomechanical fatigue load. Background technique [0002] Nickel-based superalloys are used as high-temperature structural materials due to their excellent strength, hardness, toughness, corrosion resistance and high temperature resistance. Nickel-based superalloy material technology has developed with the technical needs of energy and power, petrochemical, aerospace and other technologies, and is mainly used in high-temperature components of products and equipment in important industrial fields, such as aeroengine turbine blades, turbine disks and combustion chambers. Although nickel-based superalloys have many excellent physical and chemical properties, for aeroengine turbine blades, the thermomechanical fatigue (TMF) load will cause a lot of damage to the blades during service. F...

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Problems solved by technology

The advantage of method (1) is that the prediction process is very simple, but because it only focuses on the macroscopic scale and lacks the mechanism research on the grain microscopic scale, although the equation is simple and the parameters are easy to obtain, it lacks physical meaning and the technical acceptance is not high

For the method (2), the prediction step is very difficult, the equation expression is more complicated, there are many material parameters, the fitting process of the parameters is cumbersome and lacks experimental support, so the accuracy is insufficient, which greatly reduces the accuracy of the calculated life, and the parameters The value spans across scales and is not suitable for engineering applications

So far, researchers at home and abroad have not proposed a reliable and clear physical meaning based on the fatigue, creep and oxidation interaction life prediction method of nickel-based superalloy blades under thermomechanical fatigue loads.

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