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For nuclear power generation as a carbon‐neutral energy source, in‐vessel retention (IVR) must be implemented to maintain the structural integrity of nuclear reactor pressure vessel (RPV) for more than 72 h under severe accidental conditions. This technology requires accurate prediction of creep deformation and life of RPV material being operated under pressure and extremely high‐temperature gradient. The current work develops a simplified deformation‐mechanism‐based true‐stress (DMTS) model for creep behavior/life‐prediction of SA508 Gr.3 steel, a typical RPV material, above the phase transformation temperatures (800–1000°C). This model is used to evaluate the time to specific creep strain (t3% and t5%) and rupture (tr), in comparison with popular empirical methods such as Orr–Sherby–Dorn (OSD) and Larson–Miller (LM). The simplified DMTS model achieves an excellent agreement with the experimental observations. The controlling deformation mechanisms are also discussed by metallurgical examinations, which provide the physical premise for the model development and application. Highlights: A simplified deformation‐mechanism‐based true‐stress (DMTS) creep model was proposed.This model predicted the creep‐strain time and life of SA508 Gr. 3 at 800–1000°C.The prediction accuracy of simplified DMTS was compared with LM and OSD methods.The dominant creep deformation mechanism was dislocation climb‐plus‐glide. [ABSTRACT FROM AUTHOR]

Recently, there has been a lot of interest in the AlCoCrFeNi2.1 eutectic high‐entropy alloys (EHEAs), which can achieve a good balance of strength and ductility. The relationship between the microstructure and mechanical properties of the alloy was established in this study by examining the microstructural evolution during heat treatment of 500–1000°C. The results show that the alloy's microstructure remained unchanged when the heat treatment temperature was lower than 700°C. With further rise above 800°C, the B2II precipitates were inspected in the L12 matrix. Besides, L12II started to be precipitated from the B2 matrix at 900°C. The tensile test results conducted at 20–1000°C showed that both the yield strength and ultimate tensile strength decreased as the temperature rose. As for the elongation, however, it increased dramatically when the testing temperature was over 800°C, being attributed to the dynamic recrystallization. The results obtained provided a fundamental understanding of high‐temperature properties for duplex HEAs. Highlights: The B2II precipitates were precipitated from the L12 at 800°C.The B2II and L12II were precipitated from the L12 and B2 over 900°C.The yield and tensile strength decreased sharply at 20–700°C and slowly at 800–1000°C.The elongation first remained stable at 20–700°C and then increased sharply at 800–1000°C. [ABSTRACT FROM AUTHOR]