Establishment of unified creep–fatigue life prediction under various temperatures and investigation of failure physical mechanism for Type 304 stainless steel

Abstract

Investigations into creep-fatigue life and the corresponding failure physical mechanism are crucial for guaranteeing the structural integrity of components.In this work, a series of strain-controlled fatigue and creep-fatigue tests were performed at different temperatures. Then, the EBSD-TEM combinative analysis was performed to reveal the microstructure evolution. The creep failure parameter dependence derived from standard creep experimental data and their importance in further creep-fatigue employment were discussed. Resultsshow that strain energy density has better relevance than ductility in connecting with creep failure. The temperature-dependent critical strain energy density and an equivalent failure strain energy density, considering geometric effect, were incorporated with the current energy-based model, which enables creep-fatigue life scatter within a factor of 1.5. Moreover, multi-slip activations and severe slip interactions under creep-fatigue conditions were responsible for the ultimately lifetime reductions based on microstructure observations.

Prediction of creep deformation based on the Zc parameter method

“…The existence of scatter in creep deformation data leads to large uncertainties in the estimation of θ parameters and hence in the assessment of creep rupture time 11 . Xu et al 20 took into account data variability while investigating creep‐rupture life, and they posited that the scatter in creep‐rupture life occurs within a factor of 1.5.…”

Fatigue life evaluation model for various austenitic stainless steels at elevated temperatures via alloy features‐based machine learning approach

“…Therefore, the prediction of fatigue life under the different conditions in austenitic stainless steels has been performed. 6,7,[11][12][13][14][15][16] Although the well-known modified universal slop approach proposed by Manson 17 can be employed to precisely predict low cycle fatigue for materials at a specific temperature, the obtained fitting curve (ε-N curve) will not be suitable for Lei He and Wei Yong contributed equally to this work.…”

Guest editorial of virtual special issue: Structural integrity in the context of carbon neutrality

“…Undoubtedly, reducing carbon dioxide emissions is possible through boosting the effectiveness of energy conversion by increasing the operating temperature, only if the premature failure caused by creep, creep–fatigue, or their interaction can be prevented. Xu et al 2 carried out a series of strain‐controlled fatigue and creep–fatigue tests on uniform hollow specimens of type 304 stainless steel at various temperatures and explored the parameter dependence of creep failure. An energy‐based damage model was conducted for life assessments in a wide temperature range.…”