LOW-CYCLE FATIGUE PROPERTIES OF A REDUCED-ACTIVATION CR-MN AUSTENITICSTAINLESS-STEEL

The low cycle fatigue properties of a newly developed low activation a ustenitic stainless steel, the IF-B alloy for fusion reactor first wal l components, have been determined at 450 degrees C. The results are a nalysed and compared with those of AISI 316L and AMCR-0033 alloys. The fatigue life of the IF-B alloy is better than AISI 316L below a total strain range of 1.5% and better than AMCR-0033 in the whole testing r ange. The presence of a marked strain hardening is observed which satu rates at different values of stress and number of cycles depending on the total strain range imposed. The analysis of fracture surfaces by s canning electron microscopy shows that crack initiation occurs on the surface of the specimens and propagates in the transgranular mode with the presence of fatigue striations.