IN-SITU OBSERVATION OF LOW-ENERGY HYDROGEN-ION IRRADIATION DAMAGE IN COPPER

For the purpose of investigating the fundamental response of Cu exposed to plasma, low energy hydrogen ion irradiations were carried out between 30 and 300 degrees C in a transmission electron microscope, and microstructural evolution was observed in situ. Interstitial type dislocation loops were formed at all temperatures examined. The density and the size of the loops increased with increasing ion fluence and they changed into tangled dislocation structures at high fluence. Trapping of interstitials by hydrogen atoms enhances nucleation of interstitial loops. Bubbles (or cavities) were formed below 200 degrees C by an irradiation at high fluence. They were preferentially formed near dislocations due to their strong bias effect. Accumulation of defects in Cu above 100 degrees C is much lower than in Ni, Mo and stainless steel.