9Cr ferritic/martensitic(9Cr F/M)steels are considered ideal structural materials for various nuclear energy systems.However,δ-ferrite(δ),as a controlled phase,may occur in its welds.Three deposited metals with diff...9Cr ferritic/martensitic(9Cr F/M)steels are considered ideal structural materials for various nuclear energy systems.However,δ-ferrite(δ),as a controlled phase,may occur in its welds.Three deposited metals with different carbon contents(0.04,0.07,and 0.10 wt%)were investigated using experimental and finite element simulation methods.The results showed that the incomplete peritectic reaction,the incompleteδto austenite phase transition,and the segregation of ferrite-stabilized elements led to the residualδ.The amount and morphology ofδsignificantly influence the mechanical properties.After increasing the carbon content,the increase in strength comes mainly from precipitation strengthening and dislocation strengthening,the presence ofδwill reduce the strength.During the impact process,δaffects the absorbed energy for the stable crack growth through its morphology,and M_(23)C_(6)affects the crack formation energy through its quantity.By decreasing the carbon content to a certain extent,the reduction of M_(23)C_(6)content and the generation of large polygonalδcan effectively improve the toughness of 9Cr-steel deposited metals.展开更多
基金supported by the LingChuang Research Project of China National Nuclear Corporation,China Institute of Atomic Energy(E141L803J1)the Natural Science Foundation of Heilongjiang Province(No.TD2021E006).
文摘9Cr ferritic/martensitic(9Cr F/M)steels are considered ideal structural materials for various nuclear energy systems.However,δ-ferrite(δ),as a controlled phase,may occur in its welds.Three deposited metals with different carbon contents(0.04,0.07,and 0.10 wt%)were investigated using experimental and finite element simulation methods.The results showed that the incomplete peritectic reaction,the incompleteδto austenite phase transition,and the segregation of ferrite-stabilized elements led to the residualδ.The amount and morphology ofδsignificantly influence the mechanical properties.After increasing the carbon content,the increase in strength comes mainly from precipitation strengthening and dislocation strengthening,the presence ofδwill reduce the strength.During the impact process,δaffects the absorbed energy for the stable crack growth through its morphology,and M_(23)C_(6)affects the crack formation energy through its quantity.By decreasing the carbon content to a certain extent,the reduction of M_(23)C_(6)content and the generation of large polygonalδcan effectively improve the toughness of 9Cr-steel deposited metals.
