Quantification of Constitute Behavior of Heavy-ion Irradiated Steel by Means of the Small Punch Test

In order to ensure the safety and evaluate lifetime extension of nuclear power plants,it is fundamentally significant to accurately surveillance the mechanical properties of the in-pile components.Irradiation hardening and embrittlement is a major concern[1].For the in-pile surveillance specimen test,it is convenient to use miniaturized specimens(with reduced radioactivity)to characterize the mechanical properties.For irradiation experiments using energetic ion beams as a surrogate method,the limited area of the ion beam and the limited depth of ion range make it compulsory to develop miniaturized specimen technique to evaluate the mechanical properties of materials.Among all the small specimen test technique,small punch test(SPT)is the most attractive and widely used,which employs disc specimens firmly gripped between two dies and deformed vertically into a circular hole by a spherical punch[2;3].The sample strength and ductility can not be obtained straightforward due to the complicated stress state and the load deflections curve(LDC).Data are generally interpreted by semi-empirical formulations[4].To characterize the constitutive relation and directly observe the deformation mechanism of the ion irradiated material is a challenging work.

XRD Analysis of Radiation Damage Created by Energetic Sn Ions in Silicon Carbide Fiber

Silicon carbide(SiC)fiber possesses low neutron capture cross-section,low induced radioactivity,high thermal stability,low density,high specific strength,good oxidation-ablation resistance,high specific modulus,especially improved flaw tolerance and non-catastrophic mode of failure.Therefore,silicon carbide fiber is considered as a candidate structural component in advanced nuclear industry fields.The irradiation damage which silicon carbide fiber will experience cannot be ignored.In fission reactors,SiC fibers are inevitably subjected to irradiation by various fission fragments(heavy ions with up to hundreds of MeV)irradiation,which are produced via chain fission of the uranium.While in fusion reactors,the average energy of recoils produced by neutron irradiation in materials can reach several hundred keV.Most of the energy of fission fragments/recoils is deposited in the materials mainly through electronic processes(excitation and ionization of atoms along the trajectory of ions).Therefore,it is indispensable to acquire a comprehensive knowledge of the microstructure of SiC fibers under energetic-heavy-ion irradiation.

TEM Observation of Radiation Damage Created by Energetic Ar Ions in Silicon Carbide Fiber

Silicon carbide(SiC)fiber possesses low neutron capture cross-section,low induced radioactivity,high thermal stability,low density,high specific strength,good oxidation-ablation resistance,high specific modulus,especially improved flaw tolerance and non-catastrophic mode of failure.Therefore,silicon carbide fiber is considered as a candidate structural component in advanced nuclear industry fields.The irradiation damage which silicon carbide fiber will be subject to is inevitable.For structural components in fast breed reactors or in fusion reactors,the energy of PKAs(primary knocked-on atoms)produced by high-energy neutron irradiation can be several hundred keV,therefore effects of energy deposition via electronic processes(excitation and ionization)by PKAs in materials cannot be ignored.In situations of fuel cladding,materials may surfer from irradiation by fission fragments(which are heavy ions with up to hundreds of MeV).It is therefore necessary to know effects of energetic heavy-ion irradiation in silicon carbide for nuclear application.