The Research Of Evaluation Method Of Thermal Fatigue-Creep Performance

In aerospace, petroleum, chemical and other fields, fatigue and creep have been two important research subjects for the material scientists all over the world. Fatigue and creep have big impact for the structures in working normally, likely to cause damage, and even lead to casualties. And in many industrial fields, mechanical parts work under high temperature which is a much stricter working environment that will bring more dangerous caused by fatigue or creep damage. Thermal fatigue and creep have different mechanisms of injury. In fact, it is very complicated when considering fatigue and creep at the same time. So the study of high-temperature fatigue and creep becomes crucial.Nowadays, scientists all over the world are doing the research for life prediction of structures under high temperature. The analysis of thermal fatigue and creep is still in the exploratory stage. This article will start with the mechanism analysis of creep and fatigue, then introduce the mechanism and influencing factors, and declare the current research methods of high-temperature fatigue-creep, comparing and analyzing the advantages and disadvantages of the different methods. At last, according to the studies of these methods, try to improve and establish a new thermal fatigue-creep evaluation method which can be verified by experiments.In addition to studying the theories,there will be tensile test on 1Cr18Ni9 Ti to measure the performance of that material. Then do the creep tests to verify the effect of temperature on creep life. Then observe the morphology of the fractures by SEM to analyze failure mechanism of creep. Then do a creep test by the method of converting fatigue damage into creep damage to obtain prediction life based on the data of the creep test and linear superposition method. And then do another high-temperature fatigue-creep test with the same temperature to obtain actual life. At last, process the data and compare the prediction life with actual life to verify the feasibility of the life prediction method of converting from fatigue damage to creep damage.