Ratcheting behavior of Eurofer97 at 550 °C

Abstract

The components in reactor are usually exposed to cyclic loading caused by frequent startups, shutdown and load fluctuations which lead to ratcheting effect. Eurofer97 is a structural material candidate for in-vessel components of future fusion reactor. To investigate the ratcheting behavior of Eurofer97, uniaxial stress-controlled cyclic loading tests are performed at 550 °C. Ratcheting rates under various loading conditions, including various peak stresses, stress ratios and stress rates are determined to build the database of Eurofer97 for future application in the blankets of fusion reactor. An already developed unified visco-plastic constitutive model for mod.9Cr-1Mo FM steels is further applied to adapt the ratcheting behavior of Eurofer97. The developed model describes both cyclic softening in strain-controlled LCF tests and its impact on the ratcheting behavior of mod.9Cr-1Mo FM steel fairly good, at both room temperature and 550 °C. Verifying whether the current model can also describe the ratcheting behavior of Eurofer97 is a further aim of the work reported here.