Dynamic And Quasi-static Mechanical Properties And Micro-mechanism Of Neutron Irradiation High Purity Aluminum With Different Doses,pre-stress And Pre-strain Stations

Understanding and predicting the mechanical properties of metallic materials in the real service environment in the reactor and its miro-mechanism have always been one of the key problems in the field of nuclear energy safety.In view of the present serious lack of understanding of relevant experimental data,the high purity aluminum was taken as research material in this work due to its low neutron activation rate,and the change law of mechanical properties and the microscopic mechanism of high purity aluminum in simulated reactor service enviroment were studied.The following studies had been carried out:Firstly,a specimen preparation technology for neutron irradiation metals under pre-stress was established independently.A series of neutron irradiation high purity aluminum specimens with different dose,pre-stress and pre-strain stations were fabricated,which provided necessary conditions for subsequent macro/micro experimental researches.Secondly,the dynamic and quasi-static tensile and compression mechanical properties of high purity aluminum with different stations were studied by material testing machine,Hopkinson pressure and tensile bar and electromagnetically driven expanding ring.The laws of deformation and fracture properties of high purity aluminum with different stations were acquired.There probably exist an equivalent hardening and embrittlement mechanism by irradiation defects,forest dislocation and reinforced particle for matrix metals,obviously the dislocation channel is not necessary for irradiation embrittlement.Thirdly,the neutron irradiation pre-stress station can lead to tensile softening of anneal metals due to the orientation distribution of irradiation defects along pre-stress direction,meanwhile,tensile and compression pre-stress promoting irradiation annealing of pre-strain(cold-worked)metals.Finally,an embrittlement model is established basing on J-C constitutive,which successfully transforms the complex embrittlement problem into a relatively simple hardening issue.The laws of deformation and fracture characteristics of metallic materials with different dose,value of pre-stress,pre-tensile and pre-compression station,pre-strain and pre-strain station were studied in this work.The results could provide basic data and research methods for further understanding and estimating the laws of mechanical properties of metallic materials using in real service environment of reactors,which has some scientific significance and engineering value.