Creep-fatigue interaction and damage behavior in 9-12%Cr steel under stress-controlled cycling at elevated temperature: Effects of holding time and loading rate

Considering that most creep-fatigue tests were conducted under strain-controlled mode in previous works, creep fatigue behavior of 9-12%Cr steel under stress-controlled cycling at elevated temperature was investigated in this work. Particular attention was paid to the effects of holding time and loading rate on the deformation and damage behavior. Results indicated that a remarkable creep ratcheting is generally observed in the creep-fatigue tests with the stress ratio of-1. Ratcheting strain and creep damage progress faster as the holding time becomes larger or the loading rate becomes smaller, resulting in the decrease of the number of cycles to creep-fatigue failure.

Automated summary

This study investigated the creep fatigue behavior of 9-12%Cr steel under stress-controlled cycling at elevated temperature, considering most previous tests were conducted under strain-controlled mode. The effects of holding time and loading rate on deformation and damage behavior were particularly focused. The results showed that a significant creep ratcheting was generally observed in the creep-fatigue tests with the stress ratio of -1. Ratcheting strain and creep damage progressed faster with longer holding time or lower loading rate, leading to a decrease in the number of cycles to creep-fatigue failure.