Influence of Light Ions Irradiation on Fatigue Crack Propagation in Austenitic Stainless Steel

FATIGUE CRACK GROWTH IS CONSIDERED TO BE A LIMITING FACTOR FOR THE LIFE TIME OF THE FIRST WALL OF A TOKAMAK TYPE CONTROLLED THERMONUCLEAR REACTOR. AS A RE- SULT OF THE HIGH ENERGY NEUTRON SPECTRUM IN THE D-T FUSION REACTION NOT ONLY DEFECTS BUT ALSO LARGE QUANTITIES OF HELIUM DUE TO NUCLEAR TRANSMUTATION, ARE PRODUCED IN THE STRUCTURAL MATERIALS. ONE WAY OF SIMULATING THE DAMAGE OF HIGH ENERGY NEUTRONS IS TO USE LIGHT IONS BY MEANS OF A CHARGED PARTICLE ACCELERATOR.IN ORDER TO ACHIEVE HOMOGENEOUS IRRADIATION AND ADEQUATE HEAT REMOVAL IT IS NE- CESSARY THAT SPECIMEN THICKNESS BE LIMITED TO <- 200 / UM. THE POSSIBILITY OF OBTAINING VALID FATIGUE CRACK GROWTH DATA FROM SUCH SPECIMENS, WHICH CAN BE EXTRAPOLATED TO LARGER STRUCTURES BY USING LINEAR ELASTIC FRACTURE MECHANISMS APPROACH, HAS BEEN PREVIOUSLY DEMONSTRATED. IN THE PRESENT WORK TYPE 316 STAINLESS STEEL SPECIMENS WERE IRRADIATED IN A SUITABLE IRRADIATION CHAMBER USING A VARIABLE ENERGY CYCLOTRON. FATIGUE CRACK GROWTH UNDER CYCLIC TENSILE STRESS WAS MEASURED UNDER SIMULTANEOUS 18 MEV PROTON IRRADIATION PRODUCING A DISPLACEMENT DAMAGE RATE OF THE ORDER OF 10-7 DPA S-1. IN THE MEANTIME THE SAME TYPE OF SPECIMENS WERE IMPLANTED USING A MUCH SIMPLER SPECIMEN CHAMBER, WITH 38 MEV ALPHA-PARTICLES TO BOTAIN SEVERAL HUNDREDS APPM HELIUM (UP TO 800 APPM) AND TESTED AFTER APHA-BOMBARDMENT USING A CONVENTIONAL MECHANICAL TE- STING MACHINE. IT WAS FOUND THAT LIGHT IONS IRRADIATION HAD ONLY A SLIGHT INFLUENCE ON FATIGUE CRACK GROWTH AT 500 DEGREES C IN TYPE 316 STAINLESS STEEL

FENICI Paolo; 

1995-03-15

JRC5213

https://publications.jrc.ec.europa.eu/repository/handle/JRC5213,