To study the effect of tungsten, vanadium and tantalum on the microstructures in CLAM （China Low Activation Martensitic） steel after irradiation respectively, the microstructures of Fe-M （M= V ,W, Ta） model alloys were investigated after implanted deuterium ions using an ion accelerator at 773 K. After implanted deuterium ion, TEM （Transmission Electron Microscope） observation and EDX （Energy Dispersive X-ray Spectrom） analysis have been carried out. The result showed that tiny voids were observed in all model alloys after implanted the same dose of deuterium ions. The swelling rate in FeTa alloy was the smallest among the three alloys. Unlike FeW and FeV alloys, there was the segregation in FeTa alloy under a fluence of 5×1017D＋ /cm2 at 773 K. A theoretical analysis showed that the void growth in FeTa alloy slowed down due to tantalum segregation near voids. It indicates that tantalum plays an important role in the improved irradiation resistance of CLAM steel.
As Reduced Activation Ferritic/Martensitic (RAFM) steel is considered the primary candidate for use as a structural material in fusion power reactors,many countries are developing different kinds of RAFM.China is developing new CLAM (China Low Activation Martensitic) steel.The study investigates microstructural changes in CLAM steel implanted with deuterium ions induced by 1250 keV electron irradiation from R.T.to 873 K,and observes both the growth and shrinkage of the defect clusters produced by deuterium ion implantation under the electron irradiation.
China Low Activation Martensitic(CLAM) steel is being studied to develop the structural materials for a fusion reactor,which has been designed based on the well-known 9Cr1.5WVTa steel.The effect of tempering temperature on hardness and microstructure of CLAM steel was studied.The strength of CLAM steel increased by adding silicon,and the ductility remained constant.Conversely,while CLAM steel maintained good ductility with the addition of yttrium,its tensile strengths were greatly degraded.Behaviors under electron irradiation of CLAM steel were examined using the high voltage electron microscope.Electron irradiation at 450℃ formed many voids in CLAM steel with basic composition,whereas CLAM with silicon steel did not change the microstructure significantly.
The microstructure and nano-hardness of the pure copper and oxide dispersion-strengthened（ODS） copper alloy subjected to 1.4 Me V Au ions irradiation at room temperature were investigated. After irradiation, dislocation-loops form in both materials, while voids can only be generated in the pure copper. Compared with the irradiated pure copper, larger average diameter and lower number density of irradiation-induced dislocation-loops were detected in the ODS copper alloy, revealing that high-density dislocation and large volume of Al2O3 particles existing in the ODS copper alloy can act as effective sinks for the irradiation-induced defects. It was also detected that irradiation hardening in the ODS copper alloy is lower than that in the pure copper. The microstructure and nano-hardness results reveal that the ODS copper alloy has a better irradiation tolerance than the pure copper. In addition, the average diameter of the Al2O3 particles in the ODS copper alloy decreases after irradiation, because the Al–O chemical bonds are decomposed and the atoms are redistributed in the matrix during the irradiation process. This work reveals that the irradiation tolerance of the copper can be effectively enhanced by adding nano-sized Al2O3 particles into the matrix.
Jing ZhangYong-Qin ChangZhi-Meng GuoPing-Ping LiuYi LongFa-Rong Wan
