Method for forecasting high-temperature-alloy creep life

Abstract

The invention provides a method for forecasting the high-temperature-alloy creep life. The method includes the steps that on the basis of the theta projection method, the factor that changes of true stress are caused by changes of the material shape in the creep process is introduced, the correction theta projection method is obtained, and the concrete form is epsilon= theta1*(1-exp(theta2*(1+theta5*epsilon)*t))+theta3*(exp(theta4*(1+theta5*epsilon)*t)-1). The method can be used for forecasting a creep curve at the whole homogeneous deformation stage through initial data from the first stage to the third stage of the creep curve, and the obtaining time of creep data can be shortened. Meanwhile, the method can be used for forecasting creep curves under other creep conditions, and the forecasting process comprises forecasting of the creep rupture time under the some creep condition and the creep interruption time corresponding to some creep strain. The method is simple, reliable and suitable for different-type high temperature alloy and engineering application, and has broad prospects in the aspect of high-temperature-alloy creep life management.

Description

technical field [0001] The invention belongs to the application of material science and engineering technology, in particular to a method for predicting the creep life of a superalloy. Background technique [0002] Since the 1930s, countries around the world began to study superalloys, and developed rapidly in the next half century. With its excellent high temperature strength, good oxidation resistance and thermal corrosion resistance, good fatigue performance, fracture toughness and other comprehensive properties, superalloys are widely used in the manufacture of turbine blades, guide vanes, turbine High-temperature components such as disks, high-pressure compressor disks, and combustion chambers have become irreplaceable key materials for hot-end components of military and civilian gas turbine engines. [0003] Superalloys usually fail due to creep deformation during service, resulting in huge losses. Therefore, if the creep time of the superalloy can be accurately pr...

AI Technical Summary

Problems solved by technology

However, the θ projection method is based on ideal creep conditions, that is, the temperature and stress are constant; in the real creep process, the creep engineering stress is constant, and the cross-section of the creep sample gradually shrinks as the strain increases. , resulting in a gradual increase in the creep true stress, which contradicts each other

Since the stress change caused by the shape change in the creep process is unavoidable, and will cause the creep life to be lower than the creep life under constant stress, so that the θ projection method equation obtained by simulating the creep interruption curve is predicted to be higher under the same conditions The result of the creep time corresponding to the strain is too large; what's more, for the creep curve with a large creep strain, the curve does not conform to the law of the θ projection method

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